SECTION 3- Risk Assessmentboonslick.org/.../uploads/2011/09/SECTION-3-Part-I-Risk-Assessment… · Missouri: avalanches, coastal erosion, coastal storms, hurricanes, tsunamis, and

Warren County Hazard Mitigation Plan August 2011

Section 3 28

SECTION 3- Risk Assessment

Requirement §201.6(c)(2): [The plan shall include] A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards.

The risk assessment process identifies and profiles relevant hazards and assesses the

exposure of lives, property, and infrastructure to these hazards. The goal of risk assessment is

to estimate the potential losses in Warren County, including loss of life, personal injury, property

damage, and economic loss, from a hazard event. The risk assessment process allows

communities in Warren County to better understand their potential risk from natural hazards and

provides a framework for developing and prioritizing mitigation actions to reduce risk from future

hazard events.

The risk assessment for Warren County and its jurisdictions followed the methodology

described in the FEMA publication 386-2, Understanding Your Risks: Identifying Hazards and

Estimating Losses (2002), which includes a four-step process:

Identify Hazards

Profile hazard Events

Inventory Assets

Estimate Losses

This section is further divided into three parts: hazard identification, hazard profiles, and

vulnerability assessment:

Section 3.1 Hazard Identification identifies the hazards that threaten the entire

county and describes why some hazards have been omitted from further

consideration.

Section 3.2 Hazard Profiles discusses the threat to the planning area and

describes previous occurrences of hazard events and the probability of future

occurrence.

Section 3.3 Vulnerability Assessment assesses the County’s total exposure to

natural hazards, considering critical facilities and other community assets at risk, and

assessing growth and development trends.


Section 3 29

Multi-Jurisdictional Risk Assessment

For this multi-jurisdictional plan, the risk assessment assesses each jurisdiction’s risks where

they deviate from the risks facing the entire Warren County. Warren County is not a large

county (431 square miles) and is fairly uniform in terms of climate and topography as well as

construction characteristics and development trends. Accordingly, overall hazards and

vulnerability do not vary greatly across the planning area for most hazards.

3.1 Hazard Identification

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type…of all natural hazards that can affect the jurisdiction.

3.1.1 Methodology

All the hazards from the 2004 plan and the State Plan are included in this 2009 update except

that severe winter weather and tornadoes/severe thunderstorms are broken down into four

different hazards- hailstorm, severe winter weather, thunderstorm & high winds, and tornadoes.

The reason for discussing them separately is that there is significant increase of these hazards

in Warren County.

Based on the data limitations within the county, through the guidance provided by the State

Hazard Mitigation Plan and through the discussions with County Emergency Management

Director and the participating jurisdictions, this plan update also addresses in brief the two

natural hazards- land subsidence and levee failure. Levee failure is included with floods as it

falls within the scope of potential flooding events.

Considering the updated Missouri State Hazard Mitigation Plan 2007 and the updated

Emergency Operations Plan, there has been a gradual increase in manmade incidents, which

can be just as devastating as natural disasters in Warren County. Therefore, the following man-

made hazards are included as part of the plan update process: nuclear power plants, hazardous

materials, transportation, utility interruptions and power failures, and terrorism. The hazard

analysis provided for these hazards in this section is based on the 2004 Hazard Mitigation Plan

and the County Emergency Operations Plan.

The following natural hazards are not included in this analysis because they do not threaten


Section 3 30

Missouri: avalanches, coastal erosion, coastal storms, hurricanes, tsunamis, and volcanoes.

While expansive soils, landslides, and rock falls are recognized as hazards in Missouri, they

occur infrequently and their impacts are minimal; so they will not be profiled further in this

document.

Table 3.1 Summary of Hazard Identification Lists (2004 and 2010 Plan)

2004 Plan Hazard List 2010 Plan Hazard List

Dam failure

Drought

Earthquakes

Floods

Heat wave

Severe Winter Weather (Snow, Ice and Extreme Cold)

Tornadoes/Severe Thunderstorms

Wildfires

Dam

Drought

Earthquake

Extreme Heat

Flood/Levee Failure

Hailstorm

Severe winter weather

Thunderstorm and high winds

Tornado

Wildfire

Hazardous materials

Terrorism

Transportation

Utility Interruption & Power failure

Data on past impacts and future probability of these hazards in the Warren County planning

area was collected from following sources:

Missouri Hazard Mitigation Plan (May 2007)

Information on past hazard events from the Spatial Hazard Event and Loss Database

(SHELDUS), a component of the University of South Carolina Hazards Research Lab

that compiles county-level hazard data for 18 different natural hazard event types.

Information on past extreme weather and climate events from the National Oceanic and

Atmospheric Administration’s (NOAA) National Climatic Data Center.

Federal Disaster Declarations from the Federal Emergency Management Agency

(FEMA)

The U.S. Geological Survey (USGS) and the Center for Earthquake Research and

Information (CERI) were major sources for earthquake information.

The Dam Safety Division of Missouri (DNR) provided major information concerning

dams.


Section 3 31

Other sources included Missouri Department of Natural Resources (MDNR), Missouri

Department of Conservation (MDC), county officials; existing county, regional and state

plans; reports on the floods of 1993 and 1995; position papers on transportation issues;

and information from local residents (sources are indicated where data is cited).

3.1.2 Disaster Declaration History

One method used by the HMPC to prioritize hazards was to examine events that triggered

federal and/ or state disaster declarations. Federal and/or state declarations may be granted

when the severity and magnitude of an event surpasses the ability of the local government to

respond and recover. Disaster assistance is supplemental and sequential. When the local

government’s capacity has been surpassed, a state disaster declaration may be issued,

allowing for the provision of state assistance. Should the disaster be so severe that both the

local and state governments’ capacities are exceeded; a federal emergency or disaster

declaration may be issued allowing for the provision of federal assistance.

The federal government may issue a disaster declaration through FEMA, the U.S. Department

of Agriculture (USDA), and/or the Small Business Administration. FEMA also issues emergency

declarations, which are more limited in scope and do not include the long-term federal recovery

programs of major disaster declarations. Determinations for declaration type are based on scale

and type of damages and institutions or industrial sectors affected.

A USDA disaster declaration certifies that the affected county has suffered at least a 30 percent

loss in one or more crop or livestock areas and provides affected producers with access to low-

interest loans and other programs to help mitigate disaster impacts. In accordance with the

Consolidated Farm and Rural Development Act, counties neighboring those receiving disaster

declarations are named as contiguous disaster counties and are eligible for the same

assistance. Table below lists federal disaster declarations received by Warren County. Each of

the disaster events affected multiple counties; estimated damages reflect total losses to all

counties.

Table 3.2

Declaration Number

Declaration Date Disaster Description Counties included Estimated damage

FEMA-1676-DR January 14, 2007 Severe Winter Storms and Flooding

Barry, Barton, Callaway, Camden , Christian, Cole, Crawford, Dade, Dallas , Dent, Franklin , Gasconade, Greene, Hickory , Jasper, Laclede, Lawrence , Lincoln , Maries, McDonald, Miller, Montgomery , Newton , Osage, Phelps,

$35 million


Section 3 32

Declaration Number

Declaration Date Disaster Description Counties included Estimated damage

Polk, Pulaski, St. Charles , St. Clair, St. Louis , Stone, Warren , Webster, Wright, and the independent City of St. Louis for debris removal and emergency protective measures (Categories A and B), including direct Federal assistance.

FEMA-3281-DR December 12, 2007

Severe Winter Storms All 114 Missouri Counties and the Independent City of St.Louis

NA

FEMA-1736-DR December 27, 2007

Severe Winter Storms Adair, Andrew, Atchison, Audrain, Barton, Benton, Boone, Buchanan, Caldwell, Callaway, Camden, Cedar, Clinton, Cole, Dade, Daviess, DeKalb, Gentry, Grundy, Harrison, Hickory, Holt, Jasper, Lincoln, Linn, McDonald, Mercer, Miller, Moniteau, Montgomery, Morgan, Newton, Nodaway, Osage, Pike, Putnam, St. Clair, Schuyler, Scotland, Sullivan, Warren, and Worth Counties. Direct Federal assistance is authorized.

$28,931,081

FEMA-1749-DR March 19, 2008 Severe Storms and Flooding

Audrain, Barry, Barton, Boone, Bollinger, Butler, Callaway, Camden, Cape Girardeau, Carter, Cedar, Christian, Cole, Cooper, Crawford, Dade, Dallas, Dent, Douglas, Dunklin, Franklin, Gasconade, Greene, Hickory, Howard, Howell, Iron, Jasper, Jefferson, Laclede, Lawrence, Lincoln, Madison, Maries, McDonald, Miller, Mississippi, Montgomery, Moniteau, Morgan, New Madrid, Newton, Oregon, Osage, Ozark, Pemiscot, Perry, Phelps, Pike, Polk, Pulaski, Reynolds, Ripley, St. Charles, St. Clair, St. Francois, St. Louis, Ste. Genevieve, Shannon, Scott, Stoddard, Stone, Taney, Texas, Vernon, Warren, Washington, Wayne, Webster, and Wright Counties and the Independent City of St. Louis for emergency protective measures (Category B), limited to direct Federal assistance under the Public Assistance program.

$68,000,000

FEMA-3303-DR January 30, 2009 Severe Winter Storms, All 114 Missouri Counties and the Independent City of St.Louis

NA

Source: FEMA


Section 3 33

Table below lists U.S. Department of Agriculture disaster declarations for Warren County (2005-

2007).

Table 3.3 USDA Disaster No. Start Date Drought Tornadoes

Severe Storms

Below Normal Temperatures

Winter Storms

Excessive Moisture

S2119 01/01/2005 X

M1631 11/03/2006

X X

X

S2407 01/01/2006 X

M1676 12/01/2007

X X

N1736 12/06/2007

X

N873 01/12/2007

X

S2532 03/30/2007

X X

Source: USDA Farm Service Agency.

3.2 Hazard Profiles

Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the…location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

3.2.1 Methodology

Each hazard identified in Section 3.1, Hazard Identification, is profiled individually in this section

in alphabetical order for easier reference. The level of information presented in the profiles

varies by hazard based on the information available. With each update of this plan, new

information will be incorporated to provide for better evaluation and prioritization of the hazards

that affect Warren County.

The sources used to collect information for these profiles include those mentioned in Section

3.1.1 as well as those cited individually in each hazard section. Detailed profiles for each of the

identified hazards include information on the following characteristics of the hazard:

Hazard Description

This section consists of a general description of the hazard and the types of impacts it may have

on a community. It also includes a ranking to indicate typical warning times and duration of

hazard events. Definitions for these rankings are included in Table 3.4.


Section 3 34

Historical Statistics

This section describes the geographic extent or location of the hazard in the planning area and

includes the information on historic incidents and their impacts based upon the sources

described in Section 3.1 hazard Identification and the information provided by the HMPC.

Where available, maps are utilized to indicate the areas of the planning area that are vulnerable

to the subject hazard.

Probability of Future Occurrence

The frequency of past events is used to gauge the likelihood of future occurrences. Where

possible, the probability and severity of occurrence was calculated based on historical data.

Probability was determined by dividing the number of events observed by the number of years

and multiplying by 100. This gives the percent chance of the event happening in any given year.

An example would be three droughts occurring over a 30-year period, which suggests a 10

percent chance of a drought occurring in any given year. The probability was assigned a rank as

defined in Table 3.4.

Magnitude/Severity

The magnitude of the impact of a hazard event (past and perceived) is related directly to the

vulnerability of the people, property, and the environment it affects. This is a function of when

the event occurs, the location affected the resilience of the community, and the effectiveness of

the emergency response and disaster recovery efforts.

Hazard Summary

To maintain a consistent reporting format, prioritization was based on four elements of risk:

probability, magnitude/severity, warning time, and duration. Table 3.4 defines the rankings for

each element of risk. Table 3.5 lists different hazards in the county with their respective risk

criteria.

Table 3.4 Ratings for each hazard

Element/ Level Characteristics

Probability The likelihood that the hazard will occur.

4- Highly Likely Event is probable within the calendar year. Event has up to 1 in 1 year chance of occurring (1/1=100%) History of events is greater than 33% likely per year. Event is "Highly Likely" to occur

3- Likely Event is probable within the next three years.


Section 3 35

Event has up to 1 in 3 years chance of occurring (1/3=33%) History of events is greater than 20% but less than or equal to 33% likely per year Event is "Likely" to occur

2- Occasional Event is probable within the next five years. Event has up to 1 in 5 years chance of occurring (1/5=20%) History of events is greater than 10% but less than or equal to 20% likely per year Event could "Possibly" occur

1-Unlikely Event is possible within the next 10 years Event has up to 1 in 10 years chance of occurring (1/10=10%) History of events is less than or equal to 10% likely per year Event is "Unlikely" but is possible of occurring

Magnitude / Severity The deaths, injuries, or damage (property or environmental) that could result from the hazard.

4- Catastrophic Multiple deaths Complete shutdown of facilities for 30 or more days More than 50 percent of property is severely damaged

3- Critical Injuries and/or illnesses result in permanent disability Complete shutdown of critical facilities for at least two weeks 25–50 percent of property is severely damaged

2- Limited Injuries and/or illnesses do not result in permanent disability Complete shutdown of critical facilities for more than one week 10–25 percent of property is severely damaged

1-Negligible Injuries and/or illnesses are treatable with first aid Minor quality of life lost Shutdown of critical facilities and services for 24 hours or less Less than 10 percent of property is severely damaged

Warning Time

4 Minimal (or no) warning

3 6-12 Hours

2 12-24 Hours

1 24 + Hours

Duration

4 More than 1 Week

3 Less than 1 Week

2 Less than 1 Day

1 Less than 6 Hours


Section 3 36

Table 3.5 lists the identified hazards for each participating jurisdiction for Warren County

Table 3.5 Hazards Identified for each participating jurisdiction

Hazard Warren County

Innsbrook Marthasville Pendleton Warrenton Wright City

Truesdale Warren school

Wright city school

Washington school

Gasconade school

Dam X X X -- -- -- -- -- -- X --

Drought X X X X X X X X X X X

Earthquake X X X X X X X X X X X

Extreme Heat X X X X X X X X X X X

Floods/ Levee failure X X

X *

-- X X X X X X --

Hailstorms X X X X X X X X X X X

Severe winter weather X X X X X X X X X X X

Thunderstorms & High Winds X X X X X X X X X X X

Tornadoes X X X X X X X X X X X

Wild Fire -- -- X -- X -- X X -- -- --

Hazardous Materials X X X X X X X X X X X

Terrorism X X X X X X X X X X X

Transportation X X X X X X X X X X X

Utility interruptions/power failure

X X X X X X X X X X X

X Jurisdictions susceptible to a specific hazard -- Jurisdictions not susceptible to a specific hazard * jurisdictions susceptible to levee failure


Section 3 37

Table 3.6 Warren County Hazard Profile Summary

Natural hazards

Hazard Probability Magnitude/ Severity

Warning Time

Duration Total score Prioritization

Dam Occassional-2 Critical-3 1 1 7 Low

Drought Likely-3 Critical-3 1 4 11 Low

Earthquake Likely-3 Critical-3 4 1 11 Medium

Extreme Heat Likely-3 Critical-3 1 3 10 Medium

Floods/ Levee failure Likely-3 Critical-3 2 2 10 Medium

Hail Likely- 3 Limited- 2 3 1 9 Low

Severe winter weather Likely-3 Critical-3 3 3 12 High

Thunderstorms & High winds

Highly Likely-4 Limited-2 4 1 11 High

Tornadoes Highly Likely-4 Limited-2 4 1 11 High

Wild Fire Occassional-2 Limited-2 1 1 6 Low

Man made hazards

Hazardous Materials Likely-3 Limited-2 4 2 11 High

Terrorism Unlikely-1 Limited-2 4 3 10 Low

Transportation Likely-3 Critical-3 4 2 12 Medium

Utility Interruption & Power failure

Highly Likely-4 Limited-2 4 3 13 High

Note: a) Measures for Probability and Magnitude were determined by BRPC using the Warren County Hazard Mitigation Plan 2004- hazard work sheets, Missouri State Hazard Mitigation Plan, and other relevant sources. b) Hazard prioritization exercise was accomplished during the kickoff meeting. The rankings in this table were based on the committee’s own experience, their needs, and capabilities. This prioritization exercise was used as a basis for further analysis by the individual jurisdictions for prioritizing the goals and action plans. c) The total score of all the elements of risk - probability, magnitude/severity, warning time and duration were considered for prioritizing the hazards. A total score of 10, 11 and 12 received medium and high priority and scores of 6 to 9 received a low priority. d) However, lows were ranked differently from the total scores depending on the type of hazard. Drought has a total score of 11 but it received a low priority due to few major noted occurrences in the jurisdictions and it is not anticipated to damage structures. e) Terrorism has a total score of 10 and received a low priority as there were no occurrences in the County.


Section 3 38

3.2.2 Dam Failure

Hazard Description

A dam is defined by the National Dam Safety Act as an artificial barrier that impounds or diverts

water and (1) is at least 6 feet high and stores at least 50 acre-feet of water, or (2) is at least 25

feet high and stores at least 15 acre-feet.

Missouri’s DNR regulates the design, construction and maintenance of 4,100 non-federal, non-

agricultural dams that are at least 35 feet high. Dam owners have primary responsibility for the

safe design, operation and maintenance of their dams. They are responsible for providing early

warning of problems at the dam, for developing an effective emergency action plan, and for

coordinating that plan with local officials. The state has ultimate responsibility for public safety

and many states regulate construction, modification, maintenance, and operation of dams.

DNR’s Dam Safety Division maintains a database of all dams regardless of federal, state, local

or private ownership.

The failure of dams or levees can result in injuries, loss of life, and damage to property and the

environment. While levees are built solely for flood protection, dams often serve multiple

purposes, one of which may be flood control. Severe flooding and other storms can increase the

potential that dams and levees will be damaged and fail as a result of the physical force of the

flood waters or overtopping.

Dams and levees are usually engineered to withstand a flood with a computed risk of

occurrence. If a larger flood occurs, then that structure will likely be overtopped. If during the

overtopping, the dam fails or is washed out, the water behind is released as a flash flood. Failed

dams can create floods that are catastrophic to life and property, in part because of the

tremendous energy of the released water.

The problem of unsafe dams in Missouri was underscored by dam failures at Lawrenceton in

1968, Washington County in 1975, Fredericktown in 1977, and a near failure in Franklin County

in 1978.

Oversight is extremely valuable to the owners as well as those people living downstream of the

dam who could be flooded in the event the dam should fail. Dams can fail for many reasons.

The most common are:

Piping: internal erosion caused by embankment leakage, foundation leakage and

deterioration of pertinent structures appended to the dam.


Section 3 39

Erosion: inadequate spillway capacity causing overtopping of the dam, flow erosion, and

inadequate slope protection.

Structure Failure: caused by an earthquake, slope instability or faulty construction.

These failure types often are interrelated. For example, erosion, either on the surface or

internal, may weaken the dam or lead to structural failure. Additionally, a structural failure may

shorten the seepage path and lead to a piping failure.

Missouri DNR has defined three levels of hazard potential – high, significant, and low - as

accepted by the Interagency Committee on Dam Safety. The definitions are:

High: Failure or mis-operation will probably cause loss of human life.

Significant: Failure or mis-operation results in no probable loss of human life but can

cause economic loss, environmental damage, disruption of lifeline facilities, or impact

other concerns. Significant hazard potential classification dams are often located in

predominantly rural or agricultural areas but could be located in areas with population

and significant infrastructure.

Low: Failure or mis-operation results in no probable loss of human life and low

economic and/or environmental losses. Losses are principally limited to the owner’s

property.

Warning Time: Level 1 ─24+ Hours

Duration: Level 1─ Less than 6 hours


According to Missouri DNR’s Dam Safety Division in Rolla, Warren County now has 128 dams.

All Warren County dams are earthen construction. The mean dam height is 34 feet. The mean

maximum storage capacity is 429 acre-feet. (An acre-foot is one acre of water that is one foot

deep. For example, a 10-acre lake that is 10 feet deep would have a maximum storage

capacity of 100 acre-feet.) Many are less than 35 feet high and not regulated by Missouri DNR.

Therefore, people living downstream of these smaller unregulated dams are virtually at the

mercy of the dam owner’s construction and maintenance practices.

Of 125 dams, 28 are rated by Missouri DNR as ―high‖ risk. Only seven are regulated by the

State. High-hazard dams exhibit one or more characteristics: more than 30 years old; high ratio

of maximum storage to dam height; and/or high population density downstream. Below is a

summary table of the county’s high-hazard dams.


Section 3 40

Table 3.7 Warren County High-Hazard Dams

Official Name Year Built Length Ht. (ft.)

LAKE SHERWOOD DAM 1967 1000 67

OUR COUNTRY PLACE DAM 1965 760 64

WOODRIDGE LAKE DAM 1975 485 64

INNSBROOK #4 DAM 1975 700 46

DEER HOLLOW LAKE DAM 1972 500 78

ISLEY LAKE DAM 1983 400 65

MARTHASVILLE MV-5 DAM 2004 1,000 36

BROCKFELD DAM 2006 292 51

CARDINAL LAKE DAM 2001 370 44

DOGWOOD LAKE DAM 1970 430 42

DUNN LAKE DAM 1970 490 38

KOEPKE LAKE DAM 1967 650 40

LAKE ASPEN DAM 1979 650 53

LAKE KITZBUEHL DAM 2004 400 58

LAKE KONSTANZ DAM 1999 525 90

LAKE ST. GALLEN DAM 1979 410 57

LAKE WANDERFERN DAM 1976 410 54

MILLER LAKE DAM 1977 200 46

NINE ACRE LAKE DAM 1976 310 37

OWL CREEK ESTATES DAM #1 1970 480 41



SEABROOK DAM 1986 340 41

STARK LAKE DAM 1968 470 39

SUGAR HOLLOW LAKE DAM 1968 420 43

SUNNY MOUNT CHURCH DAM 1970 400 40

TRINITY LAKE DAM 1986 400 44

ALPINE LAKE DAM 2000 1279 118

The most recent earthen dam failure in Warren County occurred on May 27, 2008 at Innsbrook

on Lake Alpine which tore a section of pipe from the dam. Alpine lake is the largest private,

man-made lake in the State of Missouri. The lake is about 11 miles around its perimeter and

reaches a depth of 90 feet. The incident occurred after a period of heavy rainfall which caused a

large diameter pipe used to lower the lake failed. Part of a 36-inch spillway pipe was expelled

from the dam of the 236-acre lake. The pipe feeds an overflow spillway at the center of a

quarter-mile earthen dam at the south end of the lake.


Section 3 41

When the force of the water literally tore the section of pipe from the dam, it created an opening

in the dam which measured approximately 40 feet across.

At the time of this incident, emergency officials estimated that the water level of the lake was at

least 3 feet above the drainage pipe. Emergency personnel and officials from DNR took steps to

prevent a possible breach in the dam. The spillway and broken pipe were sealed off with a

mixture of rocks and concrete to prevent further seepage.

Location

Map 3.1 shows Warren County dams along with critical facilities

§̈¦I-70 §̈¦I-70

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Innsbrook

Warrenton

Foristell

Wright City

Truesdale

Marthasville

82018201

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UVEE

UVD

UVN

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Daniel Boone SchoolRebecca Boone SchoolBlack Hawk Middle SchoolWarren County High SchoolHoly Rosary Catholic SchoolWarrenton Christian SchoolJolly TotsReach Out Adult Day CreWarrenton Area Child Care CenterKiddie KampusLittle Lambs Lutheran PreschoolWarrenton ManorBristol ManorCountry Cove WestWhispering Pines Assisted Living

Wright City ElementaryWright City Middle SchoolWright City High SchoolGood Shepherd Lutheran Day CareUnion Basic Child Care Center

Marthasville Elementary School

Ü

0 2 4 61Miles

County boundary

Incorporated Areas

Roads

Dams

Source: Boonslick Regional Planning Commission


Section 3 42

Missouri DNR’s Division of Dam Safety completed the dam inundation maps for the high hazard

dams in Warren County. DNR employed LiDAR data extracted from ArcView using HEC-

GeoRAS, hydraulic analysis using HEC-RAS, and mapping using ArcView. DNR conducted the

analysis using the Rapid Assessment Method, and the Detailed Method. Both these methods

employ several standard assumptions about the nature of the breach and flow conditions.

The jurisdiction specific maps provided below were developed using the DNR dam inundation

maps. It can be seen from the maps that the major inundation areas are located in the

unincorporated parts of the county, Innsbrook and Marthasville.

Map 3.2 shows dams & inundation areas in Marthasville

UVD

UVO

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0 0.4 0.8 1.20.2Miles

Warren County boundary

Marthasville

Roads

Dam

Inundation area

Ü

Marthasville MV.5 Dam


Section 3 43

Map 3.3 shows dams & inundation areas in Village of Innsbrook

UVO

UVD

UVM

UVN

UVCC

UVTT

UVF

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0 1 2 30.5Miles


Innsbrook

Roads

Dams

Inundation zone

Ü


Section 3 44

Map 3.4 shows dams & inundation areas in the unincorporated area along with

population density

0 2 4 61Miles

Inundation Zone

Dams


Population density

1 Dot = 10

POP00

Ü


Section 3 45


No records were found to indicate any major dam failures in Warren County. The probability of

occurrence of dam failure is ―occasional‖.

Occasional- Event is probable within the next five years.

Magnitude/Severity

Marthasville, Washington School District (Marthasville elementary school) - ―Critical‖.

As per the maps, the unincorporated area as 14 dams. The magnitude/severity for the

unincorporated area is considered to be limited considering the population density.

Also, the Village of Innsbrook has 13 dams identified. Most of the homes located in this Village

are considered as secondary homes. Therefore, the magnitude/severity has been ranked as

limited.

Innsbrook, unincorporated areas - ―Limited‖.

Critical ─ 25–50 percent of property is severely damaged; Injuries and/or illnesses result in

permanent disability; Complete shutdown of critical facilities for at least two weeks.

Limited- 10-25 percent of property severely damaged; shutdown of facilities for more than a

week; and/or injuries/illnesses treatable do not result in permanent disability.

3.2.3 Drought

Hazard Description

The National Weather Service defines drought as ―a deficiency in precipitation over an extended

period, usually a season or more, resulting in a water shortage causing adverse impacts on

vegetation, animals, and/or people. The Missouri Drought Response Plan distinguishes

between five categories of drought, as follows:

Agricultural drought, defined by soil moisture deficiencies;

Hydrological drought, defined by declining surface water and groundwater

supplies;

Meteorological drought, defined by precipitation deficiencies;

Hydrological drought and land use, defined as a meteorological drought on one

area that has hydrological impacts in another area, i.e. a drought in the Rocky

Mountains may be significant in Missouri because the Missouri River is in part

dependent upon upstream precipitation and snow pack; and


Section 3 46

Socioeconomic drought, defined as drought impacting supply and demand of

some economic commodity.

Figure 3.1 shows the Palmer Drought Index published jointly by NOAA and the United States

Department of Agriculture (USDA).

Figure 3.1

Source: National Climatic Data Center.

The most commonly used indicator of drought and drought severity is the Palmer Drought

Severity Index (PDSI) published jointly by NOAA and the United States Department of

Agriculture. The PDSI measures the departure of water supply (in terms of precipitation and

stored soil moisture) from demand (the amount of water required to recharge soil and keep

rivers, lakes and reservoirs at normal levels). The result is a scale from +4 to -4, ranging from an

extremely moist spell to extreme drought. By relating the PDSI number to a regional index, one

can compile data that reflects long-term wet or dry tendencies.

Regional indicators such as the PDSI are limited in that they respond slowly to deteriorating

conditions. On the other hand, observing surface conditions and groundwater measurements

may provide only a snapshot of a very small area. Therefore, the use of a variety of drought

indicators is essential for effective assessment of drought conditions, with the PDSI being the

primary drought severity indicator.

Warning Time: Level 1- 24+ hours


Section 3 47

Duration: Level 4- More than 1 Week


Drought in Warren County is primarily a problem of rural water supply, especially those supplied

by small water structures. When good water becomes a scarce commodity and people must

compete for the available supply, the importance of drought severity and duration increases

dramatically.

According to the Climate Prediction Center, average annual precipitation for the St. Louis

regional area is 39 inches and the state rates Warren County for moderate drought

susceptibility. Precipitation-related impacts on time scales ranging from a few days to a few

months can include effects on wildfire danger, non-irrigated agriculture, topsoil moisture,

pasture conditions, and unregulated stream flows. Lack of precipitation over a period of several

months or years adversely affects reservoir stores, irrigated agriculture, groundwater levels, and

well water depth.

Montgomery County PWSD #1, and St. Charles County PWSD #2 are the two systems that

serve Warren County. Groundwater resources in the county are adequate to meet domestic and

municipal water needs, but due to required well depths, irrigation wells are very expensive. In

addition, the abundance of steep-slope topography generally is unsuitable for row-crop

irrigation.

Warren County lies in an area of Ordovician and Cambrian dolomites and sandstones (light blue

areas on the map) that can yield 15-500 gallons per minute depending on depth and the

producing formations. Wells in alluvial soils along the Missouri River (shown in beige) typically

yield more than 1,000 gallons per minute and the water is suitable for irrigation.

The DNR’s drought response system has four phases. Phase 1 begins when water monitoring

analysis indicates anticipated drought consequences. The situation moves into Phase 2 when

the PDSI reads -10 to -20. At the same time, stream flow, reservoir levels and groundwater

levels are below normal over a period of several months. Phase 3 is based on a PDSI between

-2 to -4 and various other factors. Phase 4, or activation of drought emergency procedures,

generally begins when the PSDI exceeds -4. Table below shows the existing water systems in

Warren County.

Table 3.8

Water System Name Type Status Source Water Type

Cedar Grove Village SUBD C A Ground Water

Dogwood lake campground Intern NC A Ground Water Emmaus Homes Inc C A Ground Water


Section 3 48

Water System Name Type Status Source Water Type

Flying J Travel Plaza NTNC A Ground Water Glenbrook Estates C A Ground Water Innsbrook C A Ground Water Lake Sherwood SUBD C A Ground Water Maple Ridge MHP C A Ground Water Marthasville C A Ground Water Midway Trailer Park C A Ground Water Montgomery CO PWSD #1 C A Ground Water Oakview Estates SUBD C A Ground Water Pleasant Oak MHP C A Ground Water St. Charles Co PWSD #2 Dutzow C A Ground Water St. Charles Co PWSD #2 Warren C A Ground Water St. Ignatius Loyola School NTNC A Ground Water Truesdale C A Ground Water Valley Lake Estates C A Ground Water Warco Manufacturing Co NTNC A Ground Water Warren County Water & Sewer Co C A Ground Water Warrenton C A Ground Water Washington Airport NC A Ground Water Wright City C A Ground Water Child Evangelism Fellowship NC I Ground Water Gateway refrigerated warehouses NTNC I Ground Water Truesdale Packaging NTNC I Ground Water

C- Community- Serves at least 15 service connections used by year-round residents or regularly serves 25 year-round residents.

NTNC- Non-Transient Non-Community- Serves at least the same 25 non-residential individuals during 6 months of the year.

NC- Transient Community- Regularly serves at least 25 non-residential individuals (transient) during 60 or more days per year.

Source: DNR, Drinking Water Watch

Location

While, no records were found to indicate any droughts in Warren County, no parts of the county

are exempt from this hazard. The hazard might affect countywide.


Overall, it is possible for Warren County to experience drought in any given year. The probability

of future occurrence of a drought is ―likely‖.

Likely- Event is probable within the next three years.

Magnitude/Severity

Drought impacts are wide-reaching and may be economic, environmental, and/or societal.

Drought conditions can also cause soil to compact and not absorb water well, potentially making


Section 3 49

an area more susceptible to flooding. An ongoing drought may also leave an area more prone to

wildfires. Water supply can also be of concern during periods of prolonged drought. The

magnitude/severity of drought is ―critical‖.



3.2.4 Earthquake

Hazard Description

According to SEMA, earthquakes can be defined as shifts in the Earth’s crust causing the

surface to become unstable. This instability can manifest itself in intensity from slight tremors to

large shocks. The Earth’s crust is made up of gigantic plates, commonly referred to as tectonic

plates. These plates form what is known as lithosphere and vary in thickness from 6.5 miles

(beneath oceans) to 40 miles (beneath mountain ranges) with an average thickness of 20 miles.

These plates ―float‖ over a partly melted layer of crust called the athenosphere. The plates are

in motion and where one plate joins another, they form boundaries. Pressures on the North

Atlantic ridge affecting the eastern side of the North American plate and movements along the

San Andreas Fault by the Pacific plate have reactivated the subterranean faults in the

Mississippi embayment.

Warning Time: Level 4- Minimal (or no) warning

Duration: Level 1- Less than 6 Hours.


Three earthquake zones -- the New Madrid Fault, the Wabash Valley Fault and the Illinois Basin

-- could affect Warren County because of their close proximity. Of these three, the New Madrid

poses the greatest threat. During the winter of 1811-1812 three earthquakes estimated to have

been magnitude 7.5 or greater were centered in the New Madrid fault in southeast Missouri.

Thousands of aftershocks continued for years.

Significant earthquakes, each about magnitude 6, occurred in 1843 near Marked Tree,

Arkansas, and on October 31, 1895 near Charleston, Missouri. In November 1968 a magnitude

5.5 earthquake centered in southeastern Illinois caused moderate damage to chimneys and

walls at Hermann, St. Charles, St. Louis, and Sikeston, Missouri. The felt areas include all or

portions of 23 states. Other earthquakes have occurred throughout southeastern parts of


Section 3 50

Missouri. Smaller, but still destructive, earthquakes are even more likely, according to the

Missouri Seismic Safety Commission.

Location

While, no records were found to indicate any earthquake events in Warren County, no parts of

the county are exempt from this hazard. The hazard might affect county wide.


Based on the history of the New Madrid Fault and the January 2003 estimates, Warren County

stands a 20-33% chance of experiencing an earthquake of magnitude 6.0 or greater within the

next 50 years. Since Warren County lies within a good distance from the New Madrid Fault,

small earthquakes usually are not noticeable. The more severe threat stems from an

earthquake producing Modified Mercalli impact levels of VII-XIII. According to SEMA, a major

earthquake affecting Warren County definitely is expected. The probability of future occurrence

of an earthquake is ―likely‖.


Magnitude/Severity

The amount of energy released during an earthquake is most commonly expressed on the

moment magnitude scale and is measured directly from energy released from the fault or

epicenter as recorded on seismographs. Another measure of earthquake magnitude is intensity.

Intensity is an expression of the amount of shaking at any given location on the surface as felt

by humans and defined by the Modified Mercalli Intensity Scale. It is typically the greatest cause

of losses to structures during earthquakes and is determined by many factors including distance

from epicenter and soil types.

The magnitudes of the 24 recent earthquakes in the New Madrid fault ranged from 1.1 to 2.4.

None of these quakes impacted Warren County in any way. However, the scientists from the

U.S. Geological Survey (USGS) and the Center for Earthquake Research and Information at the

University of Memphis (CERI) recently updated their forecast.

Figure below shows the projected earthquake intensities map for the State of Missouri.

According to Missouri State Emergency Management Agency, Warren County is at risk for a

Level VI impact on the Modified Mercalli Intensity Scale from a 6.7 earthquake, Level VII from a

7.6 earthquake and Level VIII from a 8.6 earthquake.


Section 3 51

Figure 3.2 Projected Earthquake intensities map

The following list shows the abbreviated description of the 12 levels of Modified Mercalli

intensity.

I. Not felt except by a very few under especially favorable conditions.

II. Felt only by a few persons at rest, especially on upper floors of buildings.

III. Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many

people do not recognize it as an earthquake. Standing motor cars may rock slightly.

Vibrations similar to the passing of a truck. Duration estimated.

IV. Felt indoors by many, outdoors by few during the day. At night, some awakened.

Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy

truck striking building. Standing motor cars rocked noticeably.


Section 3 52

V. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable

objects overturned. Pendulum clocks may stop.

VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen

plaster. Damage slight.

VII. Damage negligible in buildings of good design and construction; slight to moderate in

well-built ordinary structures; considerable damage in poorly built or badly designed

structures; some chimneys broken.

VIII. Damage slight in specially designed structures; considerable damage in ordinary

substantial buildings with partial collapse. Damage great in poorly built structures. Fall

of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.

IX. Damage considerable in specially designed structures; well-designed frame structures

thrown out of plumb. Damage great in substantial buildings, with partial collapse.

Buildings shifted off foundations.

X. Some well-built wooden structures destroyed; most masonry and frame structures

destroyed with foundations. Rails bent.

XI. Few, if any (masonry) structures remain standing. Bridges destroyed. Rails bent

greatly.

XII. Damage total. Lines of sight and level are distorted. Objects thrown into the air.

Abridged from The Severity of an Earthquake, a U. S. Geological Survey General Interest Publication.

The magnitude/severity of an earthquake in Warren County is ―critical‖



3.2.5 Extreme Heat

Hazard Description

According to information provided by FEMA, extreme heat is defined as temperatures that hover

10 degrees or more above the average high temperature for the region and last for several

weeks. Ambient air temperature is one component of heat conditions, with relative humidity

being the other. The relationship of these factors creates what is known as the apparent

temperature.

In addition, the NWS recently has devised a method to warn of advancing heat waves up to

seven days in advance. The new Mean Heat Index is a measure of how hot the temperatures

actually feel to a person over the course of a full 24 hours. It differs from the traditional Heat


Section 3 53

Index in that it is an average of the Heat Index from the hottest and coldest times of each day.

Figure below shows the NWS Heat index scale. To find the Heat Index from the table, see the

relative humidity along the left side of the table and the air temperature along the top. Where

the two intersect is the Heat Index for any given time of day.

Figure 3.3

Source: NOAA’s National Weather Service Heat Index, January 2009.

From 1995-2006, there were 230 fatalities in the U.S. are attributed to summer heat. According

to the National Weather Service, among natural hazards, no other natural disaster—not

lightning, hurricanes, tornadoes, floods, or earthquakes—takes a greater toll. The levels of

severity, by Heat Index apparent temperature are shown in the table below.

Table 3.9 Levels of Severity by Heat Index apparent temperature

Category Heat Index Health Hazards

Extreme Danger 130°F - Higher Heat Stroke/ Sunstroke is likely with continued exposure.

Danger 105°F - 129°F Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and /or physical activity.

Extreme Caution 90°F - 105°F Sunstroke, muscle cramps, and/or heat exhaustion possible with prolonged exposure and /or physical activity.

Caution 80°F - 90°F Fatigue possible with prolonged exposure and/or physical activity.

Source: National Weather Service Heat Index Program

http://www.hprcc.unl.edu/nebraska/heatwave.html


Section 3 54

The National Weather Service has a system in place to initiate alert procedures (advisories or

warnings) when the Heat Index is expected to have a significant impact on public safety. The

expected severity of the heat determines whether advisories or warnings are issued. A common

guideline for issuing excessive heat alerts is when the maximum daytime Heat Index is

expected to equal or exceed 105 degrees Fahrenheit (°F) and the night time minimum Heat

Index is 80°F or above for two or more consecutive days.

Warning Time: Level 1- 24+ Hours

Duration: Level 3- Less than 1 week


Of the 24 heat waves to hit St. Louis region between 1994 and 2007, 18 produced heat indices

within the ―Danger‖ range. These heat waves resulted in the following impacts:

91 deaths (no deaths reported within Warren County);

1859 injuries; and

property damage valued at $5.09 million

crop damage valued at $875,000

Table 3.10 List of Heat Waves across the Region (1994-2009)

Date Heat Index Deaths Injuries Property Damage

06/12/1994 100+ 4 55 0

07/17/1995 120 20 225 $75,000

07/28/1995 N/A 0 120 $15,000

08/01/1995 110-120 9 230 0

07/18/1998 110 0 137 0

07/18/1999 105-115 42 397 0

07/07/2001 105-110 5 61 0

07/17/2001 110-115 0 19 0

07/29/2001 105-110 0 4 0

08/01/2001 105 0 34 0

08/07/2001 102-110 1 10 0

08/21/2001 105-110 0 14 0

07/08/2002 105-110 1 26 0

07/20/2002 105-115 0 47 0

07/26/2002 105-115 0 185 0

08/01/2002 N/A 1 59 0

08/15/2003 100-105 2 54 0

08/24/2003 105-110 0 0 0


Section 3 55

Date Heat Index Deaths Injuries Property Damage

07/20/2004 105-110 0 25 0

07/20/2005 105-120 4 65 0

07/17/2006 105-110 0 12 0

07/29/2006 105-110 0 0 0

08/01/2006 100 0 59 0

08/05/2007 100-105 0 0

Totals 91 1859 $90,000


Location

Based on the statistics, extreme heat frequently strikes Warren County during its seasonal

pattern. No parts of the county are exempt from this hazard.


Although periods of extreme heat generally occur on an annual basis, events that cause

significant health impacts occur less frequently. Based on patterns of previous occurrences,

probability of future occurrence is considered ―likely‖.


Magnitude/Severity

The magnitude/severity of extreme heat for Warren County is considered as being ―critical‖.



3.2.6 Flood/Levee failure

Hazard Description

A flood is a partial or complete inundation of normally dry land areas. Riverine flooding is

defined as the overflow of rivers, streams, drains, and lakes due to excessive rainfall, rapid

snowmelt or ice. There are several types of riverine floods including headwater, backwater,

interior drainage, and flash flooding.

Flash flooding is characterized by rapid accumulation or runoff of surface waters from any

source. This type of flooding can occur within six hours of a rain event, after a dam or levee

failure, or following a sudden release of water held by an ice or debris jam. Flash floods can


Section 3 56

catch people unprepared. Because flash floods can develop in just a matter of hours, most

flood-related deaths result from this type of flooding event.

Several factors contribute to flooding. Two key elements are rainfall intensity and duration.

Intensity is the rate of rainfall and duration is how long the rain lasts. Topography, soil

conditions, and ground cover also play important roles. Most flash flooding is caused by slow-

moving thunderstorms or heavy rains. Floods, on the other hand, can be fast-rising, but

generally develop over a period of hours or days.

Urbanization further aggravates the flooding potential by increasing runoff two to six times over

what would occur on natural terrain. As land is converted from fields or woodlands to buildings

and pavement, it loses its ability to efficiently absorb rainfall. During periods of urban flooding,

streets can become swift moving rivers, while basements and viaducts can become death traps

as they fill with water.

The areas adjacent to rivers and stream banks that serve to carry excess floodwater during

rapid runoff are called floodplains. A floodplain is defined as the lowlands and relatively flat

areas adjoining rivers and streams. The term ―base flood,‖ or 100-year flood, is the area in the

floodplain that is subject to a one percent or greater chance of flooding in any given year, based

upon historical records.

Warning Time: Level 2- 12-24 Hours

Duration: Level 2- Less than a Day


The largest disaster to impact Warren County in recent years was the flood of 1993. Flash

flooding was responsible for a woman’s death as her home was swept downstream. Loss of

agricultural lands, homes, businesses, and infrastructure, as well as the temporary closing of

some local businesses, contributed to economic losses. Areas hardest hit by the flooding were

along the Missouri River in southern Warren County. Table below shows the flood events in

Warren County.

Table 3.11 Warren County flood events (1994-2008)

Date Type Deaths Injury Property

damage($) Crop damage($)

4/11/1994 River Flood 0 0 5,000,000 5,000,000

5/16/1995 Flash Flood 0 0 0 0

5/16/1995 Flash Flood 0 0 1,000 0

5/27/1995 Flash Flood 0 0 0 0


Section 3 57

Date Type Deaths Injury Property

damage($) Crop damage($)

4/28/1996 Flash Flood 0 0 0 0

5/1/1996 Flood 0 0 0 0

6/22/1997 Flash Flood 0 0 0 0

3/20/1998 Urban/sml Stream Fld 0 0 0 0

10/6/1998 Flood 0 0 0 0



6/24/2000 Flash Flood 0 0 0 0

12/4/2001 Flood 0 0 0 0

5/7/2002 Flash Flood 0 0 0 0

5/12/2002 Flash Flood 0 0 0 0

5/12/2002 Flash Flood 0 0 0 0

6/25/2003 Flash Flood 0 0 0 0

12/7/2004 Flash Flood 0 0 0 0

5/8/2007 Flood 0 0 0 5,000

2/5/2008 Flash Flood 0 0 0 0

Source: National Climatic data Center.

According to the National Mapping System, major rivers in Warren County include Missouri

River, Charrette Creek, Tuque Creek, North Fork Charrette Creek, Peruque Creek, Camp

Creek, Hickory Lick Creek, Lost Creek, Massie Creek, Little Lost Creek, Cullum Branch, Loutre

Slough, Clear Branch, Smith creek, Peers Slough, Wolf Creek, Indjan Camp Creek, Dry Creek,

Engemann Spring.

Table 3.12 Historical statistics of flash floods in Warren County (2000-2009) Date Time Description

24 June 2000 01:30 AM Rainfall up to 6 inches caused widespread flash flooding across the area. Sandbagging had to be done off Highway F in the Harvest Acres subdivision due to a flooded creek.

07 May 2002 03:30 AM Numerous creeks and small streams flooded making roads impassable.

12 May 2002 05:00 AM Rainfall of 2-4 inches caused flash flooding across the area.

25 June 2003 10:30 PM Heavy rain caused flash flooding across much of Warren County. Interstate 70 became virtually impassable in several places due to high water.

07 Dec 2004 12:45 AM Moderate to heavy rain brought several creeks out of their banks across Warren County.

08 May 2007 11:00 AM The Missouri river flooded parts of the southern border of Warren County. The flooding was limited to farmland along the river and to a few roads in the Marthasville area.

08 Feb 2008 04:15 PM 2 to 4 inches of rain fell over portions of Warren county during the afternoon and noon hours.

15 Jun 2009 07:10 AM In excess of three inches fell in a short amount of time over portions of Warren County. Hwy U at Booneslick Road was flooded and Hwy 47 was flooded in spots south of Warrenton. Also, Interstate 70 and adjacent access roads were flooded in spots near the Warren/Montgomery county line.


Section 3 58

Location

The flash flooding for Warren County is mostly confined to the 100-year floodplain and no data

suggests that it occurs outside the 100-year floodplain. An action plan has been proposed to

improve drainage of roadways in flash flood areas (Goal #1, Action Plan 1.2.6). HAZUS was

used to generate a one percent annual flood, or 100-year flood, event for major rivers and

creeks in the County. The software produces a flood polygon and flood depth grid that

represents the 100-year flood. While not as accurate as official flood maps these floodplain

boundaries are for use in GIS-based loss estimation.

Map 3.5 shows Innsbrook flood boundary

Innsbrook

Warrenton

Ü

Map showing Innsbrook floodboundary

Warren County Incorporated Areas

Interstate 70

Roads

Rivers

100 year flood boundary

A

0 0.7 1.40.35Miles


Section 3 59

Map 3.6 shows Marthasville flood boundary

¬«47

¬«94

¬«47

Marthasville

Ü

Map showing Marthasville floodboundary


Interstate 70

Roads

Rivers


A

0 0.2 0.40.1Miles


Section 3 60

Map 3.7 shows Warrenton & Truesdale flood boundary

¬«47

¬«47

§̈¦70§̈¦70

Warrenton

Truesdale

8201

8201

Ü

Map showing Warrenton & Truesdale floodboundary


Interstate 70

Roads

Rivers

100 yr floodboundary

0 0.5 1 1.50.25Miles


Section 3 61

Map 3.8 shows Wright City flood boundary

§̈¦70 §̈¦70Wright City

Foristell

Ü

Map showing Wright City floodboundary


Interstate 70

Roads

Rivers


A

0 0.5 10.25Miles


Section 3 62

Map 3.9 shows Warren County 100-year floodplain along with critical facilities

Innsbrook

Warrenton

Foristell

Wright City

Truesdale

Marthasville

82018201

§̈¦I-70 §̈¦I-70

Daniel Boone SchoolRebecca Boone SchoolBlack Hawk Middle SchoolWarren County High SchoolHoly Rosary Catholic SchoolWarrenton Christian SchoolJolly TotsReach Out Adult Day CreWarrenton Area Child Care CenterKiddie KampusLittle Lambs Lutheran PreschoolWarrenton ManorBristol ManorCountry Cove WestWhispering Pines Assisted Living

Wright City ElementaryWright City Middle SchoolWright City High SchoolGood Shepherd Lutheran Day CareUnion Basic Child Care Center

Marthasville Elementary

Ü

0 2 4 61Miles

County boundary

Incorporated Areas

Interstate 70

Roads

Lakes

100 yr floodplain


Section 3 63


Warren County faces two major risk factors for flooding. The land that forms Warren County is

included in the Missouri River basin that drains most of the northern and central part of the

state. The Missouri River flows east along the county’s southern boundary and joins the

Mississippi River some 50 miles east of the county. The southern rim of the county lies directly

in the Missouri River floodplain where most the 1993 flood damage occurred. According to the

federal government’s Flood Insurance Rating Maps (FIRM), for Warren County 15% of the land

lies within the 100-year floodplain. The majority of that 15% lies directly adjacent to Missouri

River levees.

Flood Event by Month, 1993-2008

Month # of Events

September 2

June 5

May 8

April 2

July 1

October 1

December 1

Out of 20 total floods, fourteen are flash floods, three are floods, one is a river flood, and two are

stream floods.

The probability of future occurrence of a flood in Warren County is ―likely‖.


Magnitude/Severity

Past flood events in Warren County have caused significant damage to property and agriculture,

endangered lives, and shut down critical facilities, and agriculture.

Marthasville, Washington School District (Marthasville elementary school) - ―critical‖.

Unincorporated areas, Innsbrook, Warrenton, Wright City, Truesdale, Warren School District,

Wright City School District - ―limited‖.

Critical: 25-50 percent of property severely damaged; shutdown of facilities for at least two

weeks; and/or injuries and/or illnesses result in permanent disability.




Section 3 64

Levee Failure: Associated with the riverine flooding hazard are floods caused by breaching or

failure of levees. Levees are human made structures designed to contain, control or deflect the

flow of water to provide protection from temporary flooding. Levees usually protect seasonal

flooding, and may be subject to water loading for periods of only a few days or weeks each

year.

Based on a 2007 database of levees known by the Corps, there are 66 levees in Missouri.

Twenty nine of these are considered to provide 100-year flood protection. FEMA, as part of its

floodplain map modernization effort, has identified 41 levees in Missouri as provisionally

accredited levees (PAL). It is expected that additional data on levees will become available in

upcoming years with FEMA’s efforts to certify levees nationwide for flood protection. Warren

County is categorized under the tri-county levee district along with Montgomery and Gasconade

Counties.

Location

The levee failure is confined to the south of the county where the Missouri River flows east and

joins Mississippi Rivers 50 miles east of the county. Although levees protect Route 47 from

Missouri River flooding, Charrette Creek, Toque Creek near Marthasville, and Lake Creek near

Dutzow occasionally cause flooding and road closures.

Map 3.10 shows the location of the creeks near the southern border of the county


Section 3 65

A one-day closure in 1990 resulted from flash flooding of Toque Creek. The road has been

closed three times since 1990 (twice in 1993 and once in 1995) when the Missouri River levees

failed. Both Toque Creek and Lake Creek are tributaries to Charrette Creek, which lies between

Route 47 and the Missouri River. Toque Creek and Lake Creek join with Charrette Creek so

near the Missouri River they are susceptible to combined backwater effects during Missouri

River and other significant flooding events. The jurisdiction close to the Missouri river is the City

of Marthasville.

Map 3.11 shows the levee districts in the county

Marthasville

DU

TZ

OW

LD

TUQ

UE C

REEK

SEC 2

TUQUE CREEK

HOLTMEIER

ST J

OH

NS

BO

TTO

M A

SS

N

CHARRETTE BOTTOMS SEC 4

ÜWarren County Boundary


Missouri river levees

Flood zone

AE

A 0 0.5 10.25Miles


Section 3 66

It has been noted that in case of any major flood events, there could be a major economic loss

to Warren County majorly to the City of Warrenton and Wright City. The reasons are that Hwy

47 serves as a connection between Warren County and Franklin County. Many people who

work in Warren County live in Franklin County and vice-versa. Therefore, any levee failure in

case of flood event would cause an effect on Warren County’s economy.


The probability of future occurrence of a levee failure in Warren County is ―likely‖.


Magnitude/Severity

City of Marthasville, Washington School District (Marthasville elementary school) -―critical‖.

Critical: 25-50 percent of property severely damaged; shutdown of facilities for at least two


3.2.7 Hail

Hazard Description

Hail develops in strong thunderstorms when rapidly rising currents of air, called updrafts, carry

raindrops to a height where they freeze. Other droplets of super cooled water will continue to

freeze onto the hailstones. Stronger updrafts will produce larger hailstones and they will

eventually fall out of the sky when the updraft can no longer support them.

Hailstorms cause damage to property, crops, and the environment, and harm livestock.

Vehicles, roofs of buildings and homes, and landscaping are the other things most commonly

damaged by hail. Hail has been known to cause injury and the occasional fatality to humans,

often associated with traffic accidents.

Based on information provided by the Tornado and Storm Research Organization, Table below

describes typical damage impacts of the various sizes of hail.

Table 3.13 Tornado and Storm Research Organization Hailstorm Intensity Scale

Intensity Category

Diameter (mm) Typical Damage Impacts

Hard Hail 5 No damage

Potentially Damaging

5-15 Slight general damage to plants, crops

Significant 10-20 Significant damage to fruit, crops, vegetation

Severe 20-30 Severe damage to fruit and crops, damage to glass and plastic structures


Section 3 67

Intensity Category

Diameter (mm) Typical Damage Impacts

Severe 25-40 Widespread glass damage, vehicle bodywork damage

Destructive 30-50 Wholesale destruction of glass, damage to tiled roofs, significant risk of injuries

Destructive 40-60 Bodywork of grounded aircraft dented, brick walls pitted

Destructive 50-75 Severe roof damage, risk of serious injuries

Destructive 60-90 Severe damage to aircraft bodywork

Super Hailstorms

75-100 Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open

Super Hailstorms

>100 Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open.

Source: Tornado & Storm research organization


Duration: Level 1- Less than 6 hours


The NCDC reported 23 hail events in Warren County between 1994 and March 2009. Table

below shows the number of hail events by the size of the hail. These events didn’t cause any

reported crop damages or property damages.

Table 3.14 Warren County Hail Events, 1994- March 2009

Hail Size (inches) Number of Events (1994 - March 2009)

0.75 8

0.88 3

1.00 6

1.50 1

1.75 5

Total 23

Location

Hailstorms frequently strike all of Warren County during its seasonal pattern. No parts of the

county are exempt from this hazard.


Section 3 68


Based on NCDC data, there were 23 hail events in Warren County from 1994- March 2009, an

average of 1.54 each year. Hail events producing hail 1.00 inches and larger occurred 17 times

over the same 15 year period.

The probability of future occurrence is ―likely‖.

Likely- Event is probable within the next three years. History of events is greater than 20% but

less than or equal to 33% likely per year.

Magnitude/Severity

On an average, Missourians experience hail 2-3 times a year; most of the time it is smaller than

a pea (1/4") and will cause little or no damage. The magnitude/severity of a hail storm in Warren

County is ―limited‖.



3.2.8 Severe Winter Weather (Snow, Ice and Extreme Cold)

Hazard Description

Winter storms in Missouri typically involve snow, extreme cold, and/or freezing rain (ice storms).

According to SEMA, severe winter weather events can cause various injuries, deaths and

property damage. Causes of death range from traffic accidents during adverse driving

conditions to heart attacks caused by overexertion while shoveling snow. Hypothermia or

frostbite may be considered the most direct cause of death and injury attributed to winter

weather.

Economic costs are difficult to measure. Heavy ice can bring down trees, power lines, telephone

lines, and communications towers. Power outages create an increased risk of fire as residents

seek alternative fuel sources (wood or kerosene for heat and fuel-burning lanterns or candles

for emergency lighting). Crops, trees, and livestock can be killed or injured due to deep snow,

ice or severe cold. Buildings and automobiles may be damaged from falling tree limbs, power

lines and poles. Local governments, homeowners, business owners, and power companies can

be faced with spending millions of dollars to restore services and remove debris.

According to the National Center for Health Statistics, approximately 600 adults die from

hypothermia each year, with the isolated elderly being most at risk. Also at risk are those

without shelter or live in a home that is poorly insulated or without heat. Other potential health


Section 3 69

and safety threats include toxic fumes from emergency heaters, household fires caused by

fireplaces or emergency heaters, and driving in treacherous conditions.

The National Weather Service describes different types of winter storm conditions as follows:

- Blizzard: Winds of 35mph or more with snow and blowing snow reducing visibility to

less than ¼ mile for at least three hours.

- Blowing Snow: Wind-driven snow that reduces visibility. Blowing snow may be falling

snow and/or snow on the ground picked up by the wind.

- Snow Squalls: Brief, intense snow showers accompanied by strong, gusty winds.

Accumulation may be significant.

- Snow Showers: Snow falling at varying intensities for brief periods of time. Some

accumulation is possible.

- Freezing Rain: Measurable rain that falls onto a surface whose temperature is below

freezing. This causes the rain to freeze on surfaces, such as trees, cars, and roads, forming

a coating or glaze of ice. Most freezing-rain events are short loved and occur near sunrise

between the months of December and March.

- Sleet: Rain drops that freeze into ice pellets before reaching the ground. Sleet usually

bounces when hitting a surface and does not stick to objects.

Provided by the National Weather Service, Figure below shows the relationship of wind

speed to apparent temperature and typical time periods for the onset of frostbite.

Figure 3.4 Wind Chill Chart

Source: http://www.weather.gov/os/windchill/index.shtml

http://www.weather.gov/os/windchill/index.shtml


Section 3 70




Warren County received 5 presidential major disaster declarations, and 4 USDA declarations for

this hazard, listed in the table below.

Table 3.15 Disaster Declarations in Warren County Involving Winter Storm

Declaration Date Description Declaration Type Disaster Number

January 30, 2009 Severe Winter Storms Presidential- Major Disaster Declaration

FEMA 3303-DR

March 19, 2008 Severe Winter Storms Presidential- Major Disaster Declaration

FEMA 1749-DR

December 27, 2007 Severe Winter Storms Presidential- Major Disaster Declaration

FEMA 1736-DR

December 12, 2007 Severe Winter Storms Presidential- Major Disaster Declaration

FEMA 3281-DR

January 14, 2007 Severe Winter Storms Presidential- Major Disaster Declaration

FEMA 1676-DR

December 1, 2007 Winter Storms USDA M1676

December 6, 2007 Winter Storms USDA N1736

January 12, 2007 Winter Storms USDA N873

March 30, 2007 Winter Storms USDA S2532

The NCDC reported 38 events from 1994 to March 2009. The total property damage was

estimated at $3.2M and crop damage at $2,000. Also, 15 injuries and 2 deaths were reported

during this time period.

January 14, 2007 FEMA 1676-DR: An arctic boundary settled south of the area on the 12th and

13th of January bringing subfreezing temperatures to the northwestern half of the county

warning area. Three rounds of precipitation occurred during this period, with the first being the

most destructive of all. Significant tree and limb damage was reported as a result of this storm,

together with widespread power outages.

Location

Severe winter weather events frequently strike all of Warren County during its seasonal pattern.

No parts of the county are exempt from this hazard.

Low levels of traffic allow snow or ice to accumulate on unpaved roads making it difficult to

plow. This hazard may have a lesser effect on city residents where most roads are paved and

city road crews can clear roads more frequently. On the other hand, the cities and towns can be


Section 3 71

strongly affected during severe winter weather because greater numbers of people travel within

its boundaries for work, shopping, and education.


During the 15-year period from 1994-March 2009, there were 38 recorded winter storm events

in Warren county. The probability of future occurrence of a winter storm in Warren County is

―likely‖

Likely- History of events is greater than 20% but less than or equal to 33% likely per year.

Magnitude/Severity

The magnitude/severity of a severe winter storm is ―critical‖

Critical- 25-50 percent of property severely damaged; shutdown of facilities for at least two


3.2.9 Thunderstorms and High winds

Hazard Description

Thunderstorms can produce a strong rush of wind known as a downburst, or straight-line winds

which may exceed 120 miles per hour. These storms can overturn mobile homes, tear roofs off

of houses and topple trees. Approximately 10 percent of the thunderstorms that occur each year

in the United States are classified as severe. A thunderstorm is classified as severe when it

contains one or more of the following phenomena: (1) Hail, three-quarters inch or greater; (2)

Winds gusting in excess of 50 knots (57.5 mph); or (3) A tornado.

High winds often accompany thunderstorms. High winds can result in property damage and

injury. Strong gusts can rip roofs from buildings, snap power lines, shatter windows, down trees,

and sandblast paint from cars. Other associated hazards include utility outages, arcing power

lines, debris blocking streets, dust storms, and an occasional structure fire from this natural

hazard.

Figure below shows wind zones in the United States. Missouri State comes under Zone IV with

a wind rate of 250 mph.


Section 3 72

Figure 3.5

Source: FEMA


Duration: Level 1- Less than 6 Hours


During the 15-year period from 1994 - March 2009, there were 59 thunderstorms and high wind

events recorded by NCDC. 53 were reported as thunderstorms and 6 as high wind events.

Table 3.14 shows the magnitude and number of thunderstorm and high wind events in Warren

County from 1994 – March 2009.

Table 3.16 Warren County Thunderstorm and High wind events

Magnitude No. of Thunderstorms & high winds

0 Knots 7

40-50 Knots 9

51-55 Knots 26

56-65 Knots 17

Location

Thunderstorms and high wind events frequently strike all of Warren County during its seasonal

pattern. No parts of the county are exempt from this hazard.


Section 3 73


The probability of future occurrence of thunderstorms and high winds in Warren County is

―highly likely‖.

Highly Likely- History of events is greater than 33% likely per year.

Magnitude/Severity

The magnitude/severity of thunderstorms and high winds in Warren County is ―limited‖



3.2.10 Tornadoes

Hazard Description

Tornadoes are cyclical windstorms or a violently rotating column of air. The average forward

speed of a tornado is about 30 m.p.h., but may vary from nearly stationary to 70 m.p.h. The

average pathway may vary in any direction, but the average tornado moves from southwest to

northeast. Tornadoes are most likely to occur between 3 p.m. and 9 p.m., but may ensue at any

hour of the day. Any person or structure at any location could be damaged by a tornado. The

amount of damage depends on 1) the strength of the tornado, 2) the tornado’s proximity to the

person/structure, 3) the strength of the structure, 4) how well a person is sheltered, etc.

Damage can range from very slight to total.

The Fujita Scale (F-Scale) is the standard measurement for rating the strength of a tornado. The

National Weather Service (NWS) bases this scale on an analysis of damage after a tornado to

infer wind speeds. On February 1, 2007, the NWS transitioned from the F-Scale to the

Enhanced Fujita scale (EF-Scale). The EF-Scale is considerably more complex and enables

surveyors to assess tornado severity with greater precision. Table below details both the scales.


Section 3 74

Table 3.17

Source: National Weather Service.

*** IMPORTANT NOTE ABOUT ENHANCED F-SCALE WINDS: The Enhanced F-scale still is a set of wind estimates (not measurements) based on damage. Its uses three-second gusts estimated at the point of damage based on a judgment of 8 levels of damage to the 28 indicators listed below. These estimates vary with height and exposure. Important: The 3 second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, "one minute mile" speed.




Of the reported 3 tornadoes, the most impacted in Warren County were in the vicinity of

Warrenton and Wright City.

Figure below illustrates the number of F3, F4, F5 tornadoes recorded in the United States per

3,700 square miles between 1950 and 1998.


Section 3 75

Figure 3.6 Tornado activity in the United States

The historical data since 1994 – March 2009 is shown in the table below.

Table 3.18 Warren County Tornado events: 1994- March 2009 Location or County

Date F-Scale Death Injury Property Damage

Warrenton 04/13/1998 F0 0 0 1K

Wright City 04/10/2001 F0 0 0 20K

Warrenton 03/13/2006 F0 0 0 0


Location

Tornado events are likely to occur countywide. No parts of the county are exempt from this

hazard.


The location of Warren County in Wind Zone IV makes the probability of a tornado in any given

year ―highly likely‖.


Magnitude/Severity

The magnitude/severity of thunderstorms and high winds in Warren County is ―limited‖




Section 3 76

3.2.11 Wildfires

Hazard Description

The majority of the fires, however, and the greatest acreage loss will occur during the spring fire

season, which is normally between February 15 and May 10. The length and severity of this

burning period depends on weather conditions. Spring in Missouri is noted for its low humidity

and high winds. In addition, spring is the time of the year when rural residents normally burn

their garden spots, brush piles, etc. Many landowners also still believe it is necessary to burn

the woods in the spring of the year in order to get more grass, kill ticks, and get rid of the brush.

These conditions, together with below normal precipitation and high temperatures, result in

extremely high fire danger. Depending on weather conditions, a sizable number of fires also

can occur between mid-October and late November.

Warning Time: Level 1- 24+ Hours



According to SEMA’s 2000 Hazard Analysis, wildfires are most common in the southern districts

of the state. However, it is possible for wildfires to occur in Warren County due to drought,

debris burning, and incendiary fires. Debris burning is consistently the number one cause of

wildfires. Incendiary fires, willfully set on another person’s property, continue to rank second in

the number of wildfires each year. Fires caused by natural ignition, like lightning, are rare

despite 50 to 70 thunderstorm days per year.

According to the Missouri Department of Conservation Forest Fire Reporting, in Warren County

the total number of acres burnt was 603.94. One of the residential areas near Wright city were

threatened by fire in 2004, and one other residential area in New Truxton was threatened in

2006. The reasons for the above fire incidents were either debris or unknown fire.

Location

An increased risk of wildfire occurs in areas called the WUI (Wildland Urban Interface) in

addition to the risk faced by the forested areas within the county. The 2000 Wildland-Urban

Interface in the U.S. defines a WUI as ―the area where houses meet wildland vegetation

(interface WUI) or where houses and vegetation or mixed together (intermix WUI)‖.

Within the WUI the three defined Community types that are vulnerable to Wildfire are:

- Interface Community


Section 3 77

Structures directly abut wildland fuels. There is a clear line of demarcation between

wildland fuels and residential, business, and public structures. Wildland fuels do not

generally continue into the developed area. The development density for an interface

community is usually three or more structures per acre, with shared municipal services.

- Intermix Community

Structures are scattered throughout a wildland area. There is no clear line of

demarcation; wildland fuels are continuous outside of and within the developed area.

The development density in the intermix ranges from structures very close together to

one structure per 40 acres.

- Occluded Community

Often found within a city, structures abut an island of wildland fuels (e.g. park or open

space). There is a clear line of demarcation between structures and wildland fuels. The

development density is usually similar to those found in the interface community, but the

occluded area is usually less than 1,000 acres in size.

The maps below show the wildland-urban interface for Warren County. Both Interface and

Intermix communities exist in Warren County.


Section 3 78

Map 3.11 shows the wildland-urban interface for Warren County

§̈¦70

§̈¦70

¬«47

¬«94

¬«94

¬«47

¬«47

¬«47

¬«94

¬«94

Innsbrook

Warrenton

Foristell

Wright City

Truesdale

Marthasville

82018201

Incorporated Areas

State highway

Interstate 70

County boundary

Wildland Urban Interface

High_Dens_Interface

High_Dens_Intermix

Med_Dens_Interface

Med_Dens_Intermix

Low_Dens_Interface

Low_Dens_Intermix

High_Dens_NoVeg 0 2.5 51.25MilesÜ


Section 3 79

Marthasville has a mix of high density interface, medium density interface, medium density

intermix, and low density interface.

Map 3.12 shows the wildland-urban interface for the City of Marthasville

Marthasville

¬«47

¬«94

¬«47

Incorporated Areas

State highway

Interstate 70


High_Dens_Interface

Med_Dens_Interface

Med_Dens_Intermix

Low_Dens_Interface

Ü0 0.1 0.2 0.30.05

Miles


Section 3 80

Innsbrook has a mix of medium density interface and medium density intermix.

Warrenton has a mix of high density interface, medium density interface, medium density

intermix, low density interface, and low density intermix.

Wright City has medium density intermix.

Map 3.13 shows the wildland-urban interface for the City of Warrenton, Innsbrook & Wright City

Innsbrook

Warrenton

Foristell

Wright City

Truesdale

8201

8201

§̈¦70

§̈¦70

¬«47

¬«47

County boundary

Incorporated Areas

State highway

Interstate 70

<all other values>


High_Dens_Interface

Med_Dens_Interface

Med_Dens_Intermix

Low_Dens_Interface

Low_Dens_Intermix

High_Dens_NoVeg

0 0.8 1.60.4Miles Ü


Section 3 81


Judging from the amount and location of the county’s forests, a disastrous wildfire is not likely.

Therefore, the probability of future occurrence of a wildfire is ―occasional‖.

Occasional- History of events is greater than 10% but less than or equal to 20% likely per year.

Magnitude/Severity

Although only a third of the county is forested, a wildfire in the grass and crop-covered plains of

the northern areas could produce significant crop losses. Grass grows back quickly with little

damage, but fires in forests and croplands are costly.

Marthasville, Warrenton, Warren School district - ―Critical‖

Truesdale - ―limited‖.





Manmade and Other Hazards

3.2.12 Hazardous Materials

Hazard Description

A hazardous material is any substance or material in a quantity or form that may pose a

reasonable risk to health, the environment, or property. As per the updated State Hazard

Mitigation Plan, the hazardous materials included are substances such as toxic chemicals,

fuels, nuclear wastes and /or products, and other radiological and biological or chemical agents.

In this section, hazardous materials incidents from fixed facilities and transportation accidents

are addressed.


Duration: Level 2- Less than 1 Day


Three major highways cross the county: I-70 (East-West), Hwy 47 North/South) and Hwy 94

(East -West along the Missouri River). One active railroad runs also East-West (Norfolk and

Southern). Several facilities in Warren County manufacture, store and use hazardous


Section 3 82

substances. Three pipelines run through the county; one carries ammonia, the other two carry

petroleum products. There are a number of fixed facilities in Warren County that use or store

hazardous substances. The Southern parts of the county, including Hwy 47 & 94, are located

within flood plains. Flooding in the past has resulted in run-off of agricultural chemicals and

petroleum products into the Missouri River.

In the event of a serious hazardous materials incident in Warren County, most likely it will be a

transportation-related accident. Hazardous materials are also transported daily over highways,

rail, barge traffic, air, etc. A hazardous material incident would mostly likely occur on Interstate

70 or along the Norfolk Southern Railroad. Highway 47 and 94 could also be the site of a

potential hazardous material incident, but to a lesser extent due to a lighter volume of truck

traffic.

Fixed facility accidents

The most recent earthen dam failure occurred on May 27, 2008 at Innsbrook on Lake Alpine.

Alpine lake is the largest private, man-made lake in the State of Missouri. The lake is about 11

miles around its perimeter and reaches a depth of 90 feet. The incident occurred after a period

of heavy rainfall which caused a large diameter pipe used to lower the lake failed. Part of a 36-

inch spillway pipe was expelled from the dam of the 236-acre lake. The pipe feeds an overflow

spillway at the center of a quarter-mile earthen dam at the south end of the lake. When the force

of the water literally tore the section of pipe from the dam, it created an opening in the dam

which measured approximately 40 feet across. At the time of the incident, emergency officials

estimated the water level of the lake was at least 3 feet above the drainage pipe. Emergency

personnel and officials from DNR took steps to prevent a possible breach in the dam. The

spillway and broken pipe were sealed off with a mixture of rocks and concrete to prevent further

seepage (EMissourian.com). The main concerns during the incident as outlined by the

Emergency Director Michael Daniels are as follows:

Establishing a unified command structure and developing an incident action plan.

Stopping or slowing down the flow of water from Alpine lake into the remaining

pipe that was still in place.

Identifying residential structures downstream of the dam that were impacted in

the event total dam failure occurred.

Developing contingency plans for search and rescue in the event the dam failed.


Section 3 83

Transportation accidents

According to the Missouri State Highway Patrol crash report, Warren County experienced

604 accidents (fatal, personal injury, property damage) in 2008, 658 in 2007, and 763 in 2006.

Figure 3.19 shows the major roads where the accidents occurred. Most of them have been

occurring I -70 and on the intersection of HWY 19 and HWY 161.

Figure 3.7 Major Roads prone to accidents in Warren County

Source: http://www.mshp.dps.mo.gov


The probability of future occurrence of fixed facility accidents is ―likely‖.


Magnitude/Severity

The magnitude/severity is ―limited‖.



3.2.13 Terrorism

Hazard Description

Federal Bureau of Investigation (FBI) defines Terrorism as ―the unlawful use of force or violence

against persons or property to intimidate or coerce a government, the civilian population, or any


Section 3 84

segment thereof, in furtherance of political or social objectives.‖ Terrorism causes loss of life,

injuries to people and properties, and disruptions in services. According to the State Hazard

Mitigation Plan, potential terrorist actions include the following:

Bombings, airline attacks, weapons of mass destruction (WMD) attacks, infrastructure

attacks, cyberterrorism, agroterrorism, arson, kidnappings, and assassinations.

Domestic terrorism is another form of threat which comes from white supremacists, black

separatists, animal rights/environmental terrorists, anarchists, antiabortion extremists, and self-

styled militia. According to FBI, international terrorism has been a major challenge for the United

States. This threat can be categorized into three: loosely affiliated extremists operating under

the radical jihad movement, formal terrorist organizations, and state sponsors of terrorism. The

different types of foreign terrorist organizations are listed in the State Hazard Mitigation Plan

2007.

After the attacks on September 11, 2001, parts of 22 domestic agencies were consolidated into

one department, the U.S. Department of Homeland Security (DHS), to protect the nation against

future terrorist threats. Depending on the necessity communities may receive assistance from

state and federal agencies operating within the existing Integrated Emergency Management

System. FEMA is responsible for supporting state and local response to the consequences of

terrorist attacks.




Warren County has potential targets for terrorist activities. These may include, but are not

limited to:

Federal, state, county and municipal government facilities and structures.

Military installations.

HAZMAT Facilities.

Medical facilities.

Religious facilities.

Businesses and manufacturing centers.

Airports, railroads, highways and navigable rivers.

Pipelines; power plants; public utilities; landmarks; and large public gatherings.


Section 3 85

Agriculture.

There are twenty eight Homeland Security Response Teams that operate throughout the State

of Missouri. Warren County is under Region C There are no terrorism incidents identified within

the county.


Since, there haven’t been any incidents taken place in the county; the probability of future

occurrence is ―unlikely‖

Unlikely- History of events is less than or equal to 10% likely per year.

Magnitude/Severity

The severity of a terrorist attack could vary from high to low depending on the attack. If the

attack is on a building, it would destroy the lives of those inside the building. But if the attack is

on a large urban area such as contaminating large area’s water supply, it would affect large

number of people. Therefore, the magnitude/severity is considered to be as being ―limited‖ to

―catastrophic‖ depending on the attack.



Catastrophic- Multiple deaths; Complete shutdown of facilities for 30 or more days; More than

50 percent of property is severely damaged.

3.2.14 Transportation

Hazard Description

As per the State Hazard Mitigation Plan, for the purpose of this study, transportation is defined

as the means, or system, that transfers large groups of individuals from one place to another.

This hazard addresses only those accidents that involve passenger air or rail travel that results

in accident death or injury.


Duration: Level 2- Less than 1 day


Table 3.17 shows the fatality Rates by Mode of Travel, 2001–2003 (Average Deaths per 100

Million Passenger Miles) Highway Vehicle Occupants and Transit Passengers. There were


Section 3 86

about 148 fatal accidents in the State involving commercial vehicles. An action plan has been

added which proposes to maintain an inventory of traffic incidents within the county.

Table 3.19 National Fatality Rates by mode of travel

Type of Vehicle Death Rate

Airlines 0.02

Automobiles 0.77

Vans, SUVs, Pickup Trucks 0.76

Heavy, Light, and Other Rail Vehicles

Not reported

Intercity and Commuter Railroads 0.03

Intercity Buses 0.02

Transit Buses 0.03

Source: State Hazard Mitigation Plan 2007


The probability of future occurrence is ―likely‖.


Magnitude/Severity

The magnitude/severity is ―critical‖



3.2.15 Utility Interruptions and Power failures

Hazard Description

This hazard may include electrical power, natural gas, public water supplies, and

communications systems. Utility systems exist everywhere and are subject to damage from

digging, fire, traffic accidents, and severe weather, including flooding, earthquake, and other

day-to-day events.


Duration: Level 3- Less than 1 Week


On January 30, 2002, a severe ice storm struck portions of western and northern Missouri. This

hazard was referred as the worst in Missouri’s history which left devastated and darkened

homes and businesses. Ice accumulations were over an inch and covered all the objects that

were at or below freezing. Further, the weight of the ice broke utility poles, conductors, tree


Section 3 87

limbs and other objects that could not withstand the weight of the ice. The ice storm of 2005 with

2-6 inches snow caused 2 deaths.

Utility failures could be localized. These failures impact generally on the very young or elderly,

who are more prone to health risks that are associated with resultant loss of heating/cooling

systems and with the loss of medical equipment that requires a power source.

The threat of earthquakes has been of greatest concern to the County which obstructs the

operability of the existing utilities.


Since, utilities exist throughout the County and are vulnerable to interruptions or failures, there

is a high probability that this hazard may occur at anytime or anyplace throughout the state. The

probability of future occurrence is ―highly likely‖


Magnitude/Severity

The degree of severity of these day-to-day events may be considered low. Therefore, the

magnitude/severity is ―limited‖.



Documents

SECTION 3- Risk Assessmentboonslick.org/.../uploads/2011/09/SECTION-3-Part-I-Risk-Assessment… · Missouri: avalanches, coastal erosion, coastal storms, hurricanes, tsunamis, and