UNDERSTANDING AND PREPARING FOR SEVERE WINDSTORMS IN 2011 AND BEYOND

UNDERSTANDING AND PREPARING FOR SEVERE

WINDSTORMSIN 2011 AND BEYOND

A PRIMER OF KNOWLEDGE THAT CAN MULTIPLY AND SPILL OVER FOR THE BENEFIT OF MILLIONS

Walter Hays, Global Alliance for Disaster Reduction, University of

North Carolina, USA

SEVERE WINDSTORMS TORNADOES,

HURRICANES, TYPHOONS, AND CYCLONES

THE PHYSICS OF SEVERE WINDSTORMS

SEVERE WINDSTORMS:TORNADOESHURRICANESTYPHOONSCYCLONES

BASIC PRINCIPLES OF PHYSICS UNDERPINNING WINDSTORMS

• HEAT AND HEAT FLOW

• PRESSURE AND PRESSURE FLOW

• GRAVITY FIELD

• KINETIC ENERGY

• POTENTIAL ENERGY

SEVERE WINDSTORMS TORNADOES

OCCUR OVER LAND AS THE RESULT OF INTERACTIONS OF

THE SUN, ATMOSPHERE, LITHOSPHERE, AND

BIOSPHERE

TORNADOE SEASON

• The peak tornado season is late winter through midsummer,….

• But tornadoes can happen any time of the year when the atmospheric conditions are right.

TORNADO ALLEY

• ALTHOUGH TORNADOES HAVE OCCURRED IN EVERY STATE, THEY OCCUR MOST FREQUENTLY IN “TORNADO ALLEY,” WHICH INCLUDES PARTS OF: TEXAS, OKLAHOMA, ARKANSAS, TENNESSEE, NEBRASKA, KANSAS, MISSOURI, ILLINOIS, AND IOWA.

THE PHYSICS OF TORNADOES

• TORNADOES ARE CAUSED BY THE COLLISION OF DESCENDING COLD AIR MASSESS COMING FROM THE NORTH AND ASCENDING WARM AIR MASSES COMING FROM THE SOUTH.

THE PHYSICS OF TORNADOES

• THE COLLISION CREATES A FUNNEL OF HIGH-VELOCITY WIND THAT IS VERY DESTRUCTIVE AS IT “TOUCHES DOWN” ONE OR MORE TIMES ALONG A LONG, NARROW (TYPICALLY 10-100 M) PATH.

PHYSICS OF A TORNADO

HAZARDS OF A TORNADO (AKA POTENTIAL DISASTER AGENTS)

• WIND: SPEEDS CAN REACH 500 KM/HR (300 MI/HR)

• THUNDER, LIGHTNING, AND HEAVY PRECIPITATION E EXTREME

• HAIL CAN BE VERY DAMAGING

THIRTY TO FORTY TORNADOES STRIKE FIVE

SOUTHERN STATES

Mississippi, Alabama, Arkansas, Kentucky, and Tennessee impacted

54 dead

FEBRUARY 5, 2008

MAP

TORNADOE SEASON AFFECTED BY LA NINA

• This tornado outbreak could be a consequence of La Nina, the cooling of the Pacific Ocean, which can cause changes in weather patterns around they world.

WARNING• The people had ample warning to get

out of harm’s way and take cover, …• But some of the warning sirens did not

work.

A TORNADO TOUCHES DOWN NEAR ATKINS, ARKANSAS

DEVASTATION NEAR ATKINS, ARKANSAS

DEVASTATION NEAR ATKINS, ARKANSAS

DEVASTATION NEAR ATKINS, ARKANSAS

COLLAPSE OF WAREHOUSE IN SOUTH HAVEN, MS

COLLAPSE OF WALL IN SHOPPING MALL: MEMPHIS, TN

A FIRE BROKE OUT IN A NATURAL GAS PUMPING STATION:

HARTSVILLE, TN

SEVERE THUNDERSTORM SYSTEM SEVERE THUNDERSTORM SYSTEM SPAWNS TORNADOES IN TEXAS:SPAWNS TORNADOES IN TEXAS:APRIL 24, 2008APRIL 24, 2008

A SUPERCELL

THE FUNNEL

IMPACTS IN WEST AND NORTH TEXAS

•WORST DAMAGE NEAR FT WORTH, TX WITH LOSSES ESTIMATED AT $35 MILLION•WIND SPEED REACHED 116 KM/HR (70 MI HR)

IMPACTS IN WEST AND NORTH TEXAS

•HEAVY RAIN FALL CAUSED POWER OUTAGES AND MINOR FLOODING•BASEBALL-SIZED HAIL

WIND DAMAGE

TORNADOES STRIKE IOWA AND MINNESOTA

Continuation of deadliest tornado season in a decadeAccompanied by large hailMay 25, 2008

HUGO, MINNESOTA: DEBRIS MARKS STORM'S PATH

PARKERSBURG, IOWA: DAMAGE

PARKERSBURG, IOWA: LOOKING FOR SURVIVORS

SEVERE WINDSTORMS HURRICANES, TYPHOONS, CYCLONES

CREATED IN THE WARM WATER OF OCEANS AS THE RESULT OF INTERACTIONS OF

THE SUN, ATMOSPHERE, HYDROSPHERE, ATMOSPHERE,

LITHOSPHERE, AND BIOSPHERE

HURRICANES

• In the Atlantic, Caribbean, Gulf of Mexico, and Eastern Pacific areas cyclonic tropical storms with well-formed central “eyes” and with wind speeds above 74 mph are referred to as HURRICANES.

PHYSICS: HURRICANES

TYPHOONS

• The exact same phenomenon, with clockwise rotation about the eye, in the Western Pacific Ocean region is called a TYPHOON.

PHYSICS OF A TYPHOON

SEVERE WINDSTORMS: CYCLONES

• The exact same phenomenon in the Indian Ocean region is called a CYCLONE.

WIND AND WATER PENETRATE BUILDING ENVELOPE

SEVEREWINDSTORMS

UPLIFT OF ROOF SYSTEM

FLYING DEBRIS PENETRATES WINDOWS

STORM SURGE AND HEAVY PRECIPITATION

IRREGULARITIES IN ELEVATION AND PLAN

POOR WORKMANSHIP

IGNORING NON-STRUCTURAL ELEMENTS

CAUSES OF RISK

CASE HISTORIES

HAZARDS OF A HURRICANE, TYPHOON, OR

CYCLONE

THE PHYSICAL PHENOMENA ASSOCIATED WITH A LONG, OCEANIC

TRAVEL PATH AND EVENTUAL LANDFALL

HAZARDS OF A HURRICANE/TYPHOON

(AKA POTENTIAL DISASTER AGENTS)

• WIND FIELD (COUNTER CLOCKWISE OR CLOCKWISE DIRECTION; CAT 1 (55 mph) TO CAT 5 (155 mph or greater)

• STORM SURGE• HEAVY PRECIPITATION• LANDSLIDES (MUDFLOWS)• COSTAL EROSION• TORNADOES (SOMETIMES)

“SEVERE WINDSTORMS ARE LABORATORIES”

EACH PAST EVENT PROVIDES VALUABLE LESSONS FOR POLICY

ON DISASTER RISK REDUCTION

1325+ HURRICANES: DYNAMIC LABORATORIES FOR LEARNING

• EACH HURRICANE HAS IMPORTANT TECHNICAL AND POLITICAL LESSONS THAT CAN BE INTEGRATED INTO DISASTER RISK REDUCTION. POLICY

2005: A RECORD HURRICANE SEASON

• Twenty-eight named storms occurred during the 2005 season.

• Over $100 billion in losses.

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• RECOVERY TAKES LONGER AND COSTS MORE THAN EXPECTED.

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• EVACUATION IS A COMPLEX ENDEAVOR THAT IS NOT ONLY COSTLY, BUT REQUIRES SUPERIOR PRIOR PLANNING.

LESSONS LEARNED FROM ALL SEERE WINDSTORMS

• TIMELY COMMUNICATION OF CRITICAL INFORMATION IMPROVES:

• MASS EVACUATIONS AND COMMUNITY PREPAREDNESS

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• STORM SURGE IS THE PRIMARY “KILLER “ IN HURRICANES, TYPHOONS, AND CYCLONES.

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• HIGH VELOCITY WIND LIFTS THE ROOFS OFF OF BUILDINGS AND IS A KILLER IN TORNADOES AS WELL AS IN HURRICANES AND TYPHOONS.

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• HIGH VELOCITY WIND AND PRESSURE CHANGES CAUSE BUILDINGS WITH INADEQUATE ENGINEERING DESIGN TO COLLAPSE.

LESSONS LEARNED FROM ALL SEVERE WINDSTORMS

• HEAVY PRECIPITATION, A TYPICAL OCCURRENCE, WILL FLOOD LOW-LYING AREAS ALONG THE PATH OF THE STORM..

RISK ASSESSMENT INTEGRATES RESEARCH AND SCIENTIFIC KNOWLEDGE GAINED FROM

“DISASTER LABORATORIES,” WITH EMERGING TECHNOLOGIES

INTO POLICY USING THE COMMUNITY’S POLITICAL

PROCESS.

PUBLIC POLICIES INTEGRATE TECHNICAL AND POLITICAL

SOLUTIONS FOR THE LONG-TERM BENEFIT AND HEALTH-CARE NEEDS OF PEOPLE, AND PROTECTION OF PROPERTY, INFRASTRUCTURE,

GOVERNMENT, AND ENTERPRISE IN THE COMMUNITY

COMMUNITYCOMMUNITY

DATA BASES DATA BASES AND INFORMATIONAND INFORMATION

•SEVERE WINDSTORMS•INVENTORY•VULNERABILITY•LOCATION

RISK ASSESSMENTRISK ASSESSMENT

RISK

ACCEPTABLE RISK

UNACCEPTABLE RISK

SEVERE WINDSTORM SEVERE WINDSTORM RISK REDUCTIONRISK REDUCTION

•PREVENTION/MITIGATION•PREPAREDNESS•EMERGENCY RESPONSE•RECOVERY and RECONSTRUCTION• EDUCATIONAL SURGES

POLICY OPTIONSPOLICY OPTIONS

Wind profileWind profile

Storm Hazards:Storm Hazards:-Wind pressure-Surge-Rain-Flood-Waves-Salt water-Missiles-Tornadoes

OceanOcean

Gradient WindGradient Wind