Hurricane Isaac Generic.ppt - Flood Protection …...Hurricane Isaac • Track – very vulnerable track • Forward Speed – very slow • Coastline – water had plenty of time

Hurricane Isaac

Communication Challenges and The Future

Hurricane Isaac

Communication Challenges and The Future

National Weather Service

Weather Forecast OfficeNew Orleans/Baton Rouge

National Weather Service

Weather Forecast OfficeNew Orleans/Baton Rouge

Hurricane IsaacHurricane Isaac

ChallengesChallenges

2012 Tropical Season 2012 Tropical Season

Season was quiet for Louisiana and Mississippi until IsaacSeason was quiet for Louisiana and Mississippi until Isaac

Satellite Imagery Satellite Imagery

*Tropical Storm

*Not forecast to

be a hurricane

until just before

landfall

*Asymmetric

convective

structure for

days

*Not very “eye”

catching

Tropical Storm – 1130 AM Tue Aug 28 Nearing Hurricane Strength

Tropical Storm – 1130 AM Tue Aug 28 Nearing Hurricane Strength

Hurricane Isaac – Aug 28 Night Imagery

Hurricane Isaac – Aug 28 Night Imagery

Model TracksModel Tracks

• “The Euro takes it here”

• “The GFS takes it here”

• “My model takes it here”

• “NHC takes it here”

• New alert: “The new GFS takes Isaac further west, but the new Euro goes further east”

• “The Euro takes it here”

• “The GFS takes it here”

• “My model takes it here”

• “NHC takes it here”

• New alert: “The new GFS takes Isaac further west, but the new Euro goes further east”

• ~84 hours before actual 2nd landfall

• Small portion of SE LA in the error cone


• Small portion of SE LA in the error cone

Saturday August 25, 4pmSaturday August 25, 4pm

Sunday August 26, 4amSunday August 26, 4am


• Westward shift with SE LA now inside the cone

• Hurricane Watch issued for St. Bernard, MS Coast Plaquemines

• Potential Category 2 in less than 72 hrs


• Westward shift with SE LA now inside the cone

• Hurricane Watch issued for St. Bernard, MS Coast Plaquemines




• Continued westward shift with increased impacts for SE LA

• Hurricane Watch issued for all of SE LA



• Continued westward shift with increased impacts for SE LA

• Hurricane Watch issued for all of SE LA



• H-hour based on Advisory 22 (Sunday 10am)

• Forecast onset of TS winds ~7am Tuesday (~45 hours out)

• H-hour based on Advisory 22 (Sunday 10am)

• Forecast onset of TS winds ~7am Tuesday (~45 hours out)

Sunday August 26, 4pmSunday August 26, 4pm

• ~60 hours before actual landfall

• Track nudged slightly farther westward

• Hurricane Warning issued

• All guidance suggests SLOW MOVING cat 1 or low end cat 2


• Track nudged slightly farther westward

• Hurricane Warning issued

• All guidance suggests SLOW MOVING cat 1 or low end cat 2

Sunday August 26, 4pmSunday August 26, 4pm

• H-hour based on Advisory 23 (Sunday 4pm)

• Forecast onset of TS winds 12am-3am Tuesday (~34 hours out)

• H-hour based on Advisory 23 (Sunday 4pm)

• Forecast onset of TS winds 12am-3am Tuesday (~34 hours out)

Monday August 27, 10amMonday August 27, 10am


• Track nudged very slightly westward

• Forecast category 1 at coast

• Slow forward motion and large size – Significant

storm surge threat


• Track nudged very slightly westward

• Forecast category 1 at coast

• Slow forward motion and large size – Significant

storm surge threat


Storm Surge ForecastStorm Surge Forecast

What Impacts Storm Surge?What Impacts Storm Surge?

• Track• Track

Single Track Storm Surge PlotSingle Track Storm Surge Plot

Single Track Storm Surge Plot (moved track west)Single Track Storm Surge Plot (moved track west)

Single Track Storm Surge Plot (moved track east)Single Track Storm Surge Plot (moved track east)


• Track

• Forward Speed

• Track

• Forward Speed

Gustav SLOSH estimate using 50 nm RMWGustav SLOSH estimate using 50 nm RMWGustav SLOSH estimate using 50 nm RMWGustav SLOSH estimate using 50 nm RMW

Gustav SLOSH estimate Gustav SLOSH estimate if ~10 if ~10 ktskts slowerslowerGustav SLOSH estimate Gustav SLOSH estimate if ~10 if ~10 ktskts slowerslower


• Track

• Forward Speed

• Coastline

– Bathymetry and Geographic Shape

• Track

• Forward Speed

• Coastline


Wide shelf/

gentle slope

Narrow shelf/

sharp slope

Single Track Storm Surge Plot (moved track east)Single Track Storm Surge Plot (moved track east)


• Track

• Forward Speed

• Coastline


• Radius of Mean Winds (RMW)

• Track

• Forward Speed

• Coastline


• Radius of Mean Winds (RMW)

RMW = 25 mi., “Average” Size

Actual RMW = 6 mi.

What Impacts Storm Surge?Hurricane Isaac

What Impacts Storm Surge?Hurricane Isaac

• Track – very vulnerable track

• Forward Speed – very slow

• Coastline – water had plenty of time to funnel into the lowest areas


• Radius of Mean Winds (RMW) – 45 to 50 mile RMW (double the average)

• Track – very vulnerable track

• Forward Speed – very slow

• Coastline – water had plenty of time to funnel into the lowest areas


• Radius of Mean Winds (RMW) – 45 to 50 mile RMW (double the average)

Products and Services During IsaacProducts and Services During Isaac

CurrentProducts and Services During Isaac

CurrentProducts and Services During Isaac

• Text

• Graphic

• Briefings

• PowerPoint

• Hundreds of telephone calls

• Text

• Graphic

• Briefings

• PowerPoint

• Hundreds of telephone calls

Local Action Statement Local Action Statement

Worst case storm surgepotential for all locations

Cat 2 Hurricane moving NNW 10 MPH

Worst case storm surgepotential for all locations

Cat 2 Hurricane moving NNW 10 MPH

Tropical Cyclone Coastal Flooding Impact Graphic421 am cdt Mon Aug 27, 2012

Tropical Cyclone Coastal Flooding Impact Graphic421 am cdt Mon Aug 27, 2012

• http://weather.gov/tcig

• Extreme threat level for Lake Pontchartrain and areas east of MS River

• Coastal flooding impacts defined locally and available on website next to coastal flooding potential impact graphic.

• http://weather.gov/tcig

• Extreme threat level for Lake Pontchartrain and areas east of MS River

• Coastal flooding impacts defined locally and available on website next to coastal flooding potential impact graphic.

Storm Surge Forecast Monday Aug 27, 5amStorm Surge Forecast Monday Aug 27, 5am

• ~48 hrs before actual 2nd

landfall

• ~48 hrs before actual 2nd

landfall

P-Surge of 4 Feet or moreNHC Advisory 26

10 am cdt Mon Aug 27, 2012




10 am Wed Aug 29, 2012


10 am Wed Aug 29, 2012


How did the physical science do?How did the physical science do?

Storm SurgeStorm SurgeLocation Est. Surge (feet), date, est. with

tide)

Point-a-la-Hache (Plaquemines) 12.0 9/30 13.21

Shell Beach (St Bernard) 11.07 9/29 11.02

Waveland Yacht Club (Hancock) 7.98 9/29 9.82

South of Lafitte (Jefferson) 8.5 9/31 9.47

Rigolets at Hwy 90 (Orleans) 7.0 9/30 8.88

Mandeville (St Tammany) 7.0 9/30 8.25

Bayou Liberty Slidell (St Tammany) 7.5 9/30 8.13

Gonzales Panama Canal

(Ascension)

6.5 9/30 7.96

Biloxi Back Bay (Harrison) 6.5 9/29 7.66

Pass Manchac LaPlace (St John the

Baptist)

5.5 9/30 6.99

Pilot Town (Plaquemines) 6.63 9/29 6.70

Grand Isle (Jefferson) 4.5 9/29 5.64

Wind Duration ForecastSunday Aug 26, 12pm

Wind Duration ForecastSunday Aug 26, 12pm

• Initial wind duration forecast included in the 12pm SE Task Force briefing (and also in the 2pm EM briefing):

– Tropical Storm wind duration: 24 hours for

most locations with a few locations up to 36 hours

– Hurricane force wind duration: 6 to 8 hours in areas within direct path

• Initial wind duration forecast included in the 12pm SE Task Force briefing (and also in the 2pm EM briefing):

– Tropical Storm wind duration: 24 hours for

most locations with a few locations up to 36 hours

– Hurricane force wind duration: 6 to 8 hours in areas within direct path

Wind Duration ForecastTuesday Aug 28, 7am

Wind Duration ForecastTuesday Aug 28, 7am

Location Tropical Storm Force Duration(Sustained)

Hurricane Force Duration (Along track and in squalls)

Lower PlaqueminesLower St. Bernard

24-36 hrs 6-10 hrs

South ShoreNorth Shore

Hancock County24-36 hrs 4-8 hrs

LA Florida ParishesLA River Parishes

24-36 hrs 1-3 hrs

Harrison CountyJackson County

18-24 hrs 1-3 hrs

SW MSE Central LA

18-30 hrs gusts possible

Duration forecasts were tweaked as forecasts were adjusted for

change in path and forward speed

Duration forecasts were tweaked as forecasts were adjusted for

change in path and forward speed

Rain ForecastSunday Aug 27, 12pm


• When model guidance began shifting westward and a westward shift looked likely in the NHC track, NWS New Orleans included the following in the 12pm SE Task Force and 2pm EM briefings:

“Rainfall: 12 to 16 inches. Highest threat along and east of track.”

• “Higher, up to 20 inches in rainbands”

• When model guidance began shifting westward and a westward shift looked likely in the NHC track, NWS New Orleans included the following in the 12pm SE Task Force and 2pm EM briefings:

“Rainfall: 12 to 16 inches. Highest threat along and east of track.”

• “Higher, up to 20 inches in rainbands”

Rain ForecastRain Forecast

• Forecast rainfall values from NWS New Orleans changed very little with at least 10 inches forecast across the area once the track began to shift westward

• All briefings beyond Sunday evening specifically explained that slow movement would lead to significant heavy rainfall threat

• Forecast rainfall values from NWS New Orleans changed very little with at least 10 inches forecast across the area once the track began to shift westward

• All briefings beyond Sunday evening specifically explained that slow movement would lead to significant heavy rainfall threat



• HPC graphics continue to indicate heaviest rain east of local area (farther east track)

• NWS New Orleans:“Storm total of 15 to 18

inches expected, some higher amounts possible.

Flash Flood Watch now in

effect for entire area.”

• HPC graphics continue to indicate heaviest rain east of local area (farther east track)


inches expected, some higher amounts possible.

Flash Flood Watch now in

effect for entire area.”



• HPC graphics begin to spread heavier rainfall westward


inches expected, some

higher amounts possible.”

“Slow movement means

greater threat of heavy

rain.”

• HPC graphics begin to spread heavier rainfall westward






rain.”

Rain ForecastMonday Aug 28, 4pm

Rain ForecastMonday Aug 28, 4pm

• HPC graphics spread heavy rainfall across the whole area






rain.”

• HPC graphics spread heavy rainfall across the whole area






rain.”

Rainfall AccumulationRainfall Accumulation

Radar rainfall

estimates show

large swaths of

12 to 16 inches

(red) and

averages of 6 to

12 inches

(yellow and

orange)

Estimated Isaac RainfallEstimated Isaac Rainfall

Some Rainfall TotalsSome Rainfall Totals

Location Rain Total (inches)

Pascagoula 3 NE 22.20

New Orleans Carrollton 20.66

Biloxi 17.72

Hammond 15.68

Reserve 14.84

Picayune 13.94

McComb 11.74

Robert 11.50

Galliano 10.89

Slidell 10.39

Kentwood 10.32

Baton Rouge Sherwood 9.21

River Flooding ForecastThursday Aug 30, 7am

River Flooding ForecastThursday Aug 30, 7am

Historic River Flood EventHistoric River Flood EventLocation Crest (feet)

Wolf near Landon 31.36 (record)

Wolf near Gulfport 16.50 (record)

Hobolochitto near Caesar 21.48 (record)

Tangipahoa near Kentwood 16.86 (major)

Tangipahoa near Robert 24.02 (major)

Amite near Maurepas 7.48 (major)

Pearl near Pearl River 18.54 (major)

Bogue Chitto near Tylertown 29.81 (major)

Bogue Chitto near Franklinton 22.13 (major)

Bogue Chitto near Bush 19.82 (major)

Biloxi near Wortham 26.38 (major)

Tchefuncte near Covington 26.81 (moderate)

Bogue Falaya at Camp Covington 55.15 (moderate)

Jourdan near Kiln 9.69 (moderate)

TornadoesTornadoes

County/Parish Location EF Rating

Harrison Gulfport EF-1

Jackson Ocean Springs EF-1

Jackson Pascagoula EF-2


Social Science ChallengesSocial Science Challenges

Saffir-Simpson ScaleSaffir-Simpson Scale

• Categorizes hurricanes into 5 levels of intensity based on wind speeds alone

• “Just a category 1” or “Only a tropical storm”

– Ignores other threats such as wind duration, storm surge, heavy rainfall, river flooding, etc

– Gives people a dangerous false sense of

safety/security

• Categorizes hurricanes into 5 levels of intensity based on wind speeds alone

• “Just a category 1” or “Only a tropical storm”

– Ignores other threats such as wind duration, storm surge, heavy rainfall, river flooding, etc

– Gives people a dangerous false sense of

safety/security

SLOSHSLOSH

• SLOSH graphics tied to Saffir-Simpson categories despite the fact that the Saffir-Simpson scale is now “wind-only”

• Category 1 scenarios did not accurately portray Isaac’s threat due to large size and slow motion

• NWS New Orleans attempted to combat this by briefing using category 2 graphics and explaining the higher than “typical” values

• NWS New Orleans turned to the media to help communicate these extreme impacts

• SLOSH graphics tied to Saffir-Simpson categories despite the fact that the Saffir-Simpson scale is now “wind-only”

• Category 1 scenarios did not accurately portray Isaac’s threat due to large size and slow motion

• NWS New Orleans attempted to combat this by briefing using category 2 graphics and explaining the higher than “typical” values

• NWS New Orleans turned to the media to help communicate these extreme impacts

Storm Comparisons andPersonal Experiences

Storm Comparisons andPersonal Experiences

• Every storm is different, but people have a natural tendency to draw from personal experience

– We didn’t flood in Katrina

– My house has never flooded in 50 years

– The surge forecast was similar for Gustav and

we didn’t flood then

• Every storm is different, but people have a natural tendency to draw from personal experience

– We didn’t flood in Katrina

– My house has never flooded in 50 years

– The surge forecast was similar for Gustav and

we didn’t flood then


Where do we go now?Where do we go now?

P-Surge 4 ft or moreNHC Advisory 25

4 am cdt Mon Aug 27 2012

P-Surge 4 ft or moreNHC Advisory 25

4 am cdt Mon Aug 27 2012

10% P-Surge Exceedance

“Typical Level of Confidence”

NHC Advisory 25



“Typical Level of Confidence”

NHC Advisory 25


20% P-Surge Exceedance“High Level of Confidence”

NHC Advisory 254 am cdt Mon Aug 27, 2012

20% P-Surge Exceedance“High Level of Confidence”

NHC Advisory 254 am cdt Mon Aug 27, 2012


“Higher Level of Confidence”

NHC Advisory 25



“Higher Level of Confidence”

NHC Advisory 25


50% P-Surge Exceedence

“Highest Level of Confidence”

NHC Advisory 25


50% P-Surge Exceedence

“Highest Level of Confidence”

NHC Advisory 25


Probabilistic Inundation Hurricane Surge (PIHS) Probabilistic Inundation Hurricane Surge (PIHS)

• P-Surge Exceedance – height above ground.

– 10 % - Typical Level of Confidence

– 20 % - High Level of Confidence

– 30 % - Higher Level of Confidence

– 50 % - Highest Level of Confidence

• Probability of Inundation of Hurricane Surge greater than 4 feet.

• P-Surge Exceedance – height above ground.

– 10 % - Typical Level of Confidence

– 20 % - High Level of Confidence

– 30 % - Higher Level of Confidence

– 50 % - Highest Level of Confidence

• Probability of Inundation of Hurricane Surge greater than 4 feet.

Inundation GraphicsInundation Graphics

• Datum Issues

• Pretty Picture Issues

– Pretty does not equal accuracy!

– Need to be accurate and easy to understand

– The vast majority of storm surge forecast error

is in the meteorology. In the heat of the battle, one MUST not go with one forecast graphic.

Uncertainty must play a big role

• Datum Issues

• Pretty Picture Issues

– Pretty does not equal accuracy!

– Need to be accurate and easy to understand

– The vast majority of storm surge forecast error

is in the meteorology. In the heat of the battle, one MUST not go with one forecast graphic.

Uncertainty must play a big role

The Social Science of Categories

The Social Science of Categories

• Moving away from Categories

– Products

– Graphics

– Evacuations

– Response

• Moving away from Categories

– Products

– Graphics

– Evacuations

– Response

Storm Surge WarningStorm Surge Warning

Storm Surge Warning ExampleHurricane Isaac

Storm Surge Warning ExampleHurricane Isaac

TrainingTraining

• Storm Surge Warning

• Inundation Graphics

• Probabilistic Information

• Storm Surge Science

• Concentration on Impacts not the “skinny black line” and the category

• Where to get information and how to sort out all that information

• Storm Surge Warning

• Inundation Graphics

• Probabilistic Information

• Storm Surge Science

• Concentration on Impacts not the “skinny black line” and the category

• Where to get information and how to sort out all that information

Documents

Hurricane Isaac Generic.ppt - Flood Protection …...Hurricane Isaac • Track – very vulnerable track • Forward Speed – very slow • Coastline – water had plenty of time