William LockeWilliam LockeBozeman, MTBozeman, MT

UnderstandingUnderstandingKATRINAKATRINA8/29/058/29/05

http://www.nnvl.noaa.gov/hurseas2005/Katrina1215z-050829-4kg12.jpg

• On promontories, not baysOn promontories, not bays

• 2 category 5s, 7 cat. 4s2 category 5s, 7 cat. 4s

http://www.nhc.noaa.gov/gifs/hur5005.jpg

History History (1900-(1900-1996)1996)http://www.nhc.noahttp://www.nhc.noaa.gov/pastall.shtmla.gov/pastall.shtml

• South Florida South Florida = most = most frequentfrequent

• South Texas South Texas and Miss. and Miss. Delta = Delta = secondsecond

• KatrinaKatrina

• RitaRita

Percent per year probability (historical)per 50-mile (80 km) coastline

Hurricane historyHurricane history

Cat. 3+

Hurricanes

Named storms

http://www.nhc.noaa.gov/gifs/atlhist_lowres.gif

Hurricane historyHurricane history

Cat. 3+

Hurricanes

Named storms

But – see http://wind.mit.edu/~emanuel/anthro2.htm

Miss. deltaMiss. delta

• Sea level?Sea level?– Lake Lake

PontchartraiPontchartrainn

– Lake Lake BorgneBorgne

– SW PassSW Pass

http://www.mpcnetwork.com/marinersinfo/charts/gm/2neworleans.gif

SW PASS

Mississippi delta in floodMississippi delta in flood

• Note:Note:– Sediment to GulfSediment to Gulf

1,000,000 1,000,000 ton/dayton/day

– Flooded outer Flooded outer deltadelta

– Dry diked areasDry diked areas– Vegetation/land Vegetation/land

use on use on natural natural leveeslevees http://jan.ucc.nau.edu/~rcb7/MissDelta.jpg

BayouLafourche

Topography of New OrleansTopography of New Orleans• Much of north N.O. lies well below sea Much of north N.O. lies well below sea

levellevel

• Sea water gains access through canalsSea water gains access through canals

• An uneasy truce is maintained by ~350 An uneasy truce is maintained by ~350 miles of levees.miles of levees.

From Brian Hayes (2005), American Scientist, v. 93, p. 496-499 [original map from Louisiana State University]

Natural leveesNatural levees

• Result from multiple Result from multiple floodsfloods

• Extend 2+ km from Extend 2+ km from river channelriver channel

• Are poorly Are poorly engineered!engineered!

Which way to the ocean?Which way to the ocean?

• Miss. R. is twice as long (half as Miss. R. is twice as long (half as steep) as shortcuts via the steep) as shortcuts via the Atchafalaya R. or Lake P.Atchafalaya R. or Lake P.

http://www.ssec.wisc.edu/~gumley/modis_gallery/images/MississippiDelta_20040127_1940_1000m.jpg

Atchafalaya

Mississippi

Mississippi River deltaMississippi River deltass

• Sea level stable Sea level stable for ~6000 yrfor ~6000 yr

• Delta front moves Delta front moves as river avulsesas river avulses

• Average duration Average duration <1000 yr<1000 yr

• Modern delta for Modern delta for ~1300 yr~1300 yr

• Time for a Time for a change!change!

http://www.uwgb.edu/dutchs/graphic0/geomorph/missdlt.gif

Recent sediment thicknessRecent sediment thickness• Greatest near edge of shelfGreatest near edge of shelf

[max. ~ 100 m][max. ~ 100 m]

• Can’t restore Can’t restore wetlandswetlands

• Can’t armor Can’t armor coastcoast

• Can compact and Can compact and subside subside (1-10 mm/yr)!(1-10 mm/yr)!

• S.L. S.L. 1-3 mm/yr1-3 mm/yr

• N.O. -8’ to 15’ “above” sea N.O. -8’ to 15’ “above” sea level.level.

http://coastal.er.usgs.gov/LA-subsidence/figure2.html

Levee history & failureLevee history & failure

• OvertoppingOvertopping

• Seepage Seepage through/underthrough/under the levee the levee

• Not protection - Not protection - postponementpostponement

http://web.umr.edu/~rogersda/flood_hazards/Should%20I%20Trust%20That%20Levee.htm

Courtesy USACOE

KatrinaKatrina

http://www.ssd.noaa.gov/GOES/katrina.html

Sea-surface temperaturesSea-surface temperatures

• Note Note extremely extremely warm warm waterwater

• Shallow Shallow coastal coastal waters waters commonly commonly lack cold lack cold layerslayers Image courtesy NASA-JPL

Katrina by strength and Katrina by strength and warningswarnings• Tropical Tropical

depressiondepression

• Tropical stormTropical storm

• Hurricane 1Hurricane 1

• Hurricane 2Hurricane 2

• Hurricane 3Hurricane 3

• Hurricane 4Hurricane 4

• Hurricane 5Hurricane 5http://www.nhc.noaa.gov/archive/2005/KATRINA_graphics.shtml

Katrina windsKatrina winds

Katrina modeled rainfallKatrina modeled rainfall

• Note Note max. max. EAST of EAST of track of track of storm storm eyeeye

• Same for Same for windwind

Hurricane Hurricane StructureStructure• Cyclonic (CCW) Cyclonic (CCW)

winds >74 mphwinds >74 mph

• Right side = Right side = storm wind storm wind ++ forward motionforward motion

• Left side = Left side = storm wind storm wind –– forward motionforward motion

N.O.

WavelandBiloxi

Storm surgeStorm surge

• Key variablesKey variables– Onshore windsOnshore winds– Central pressureCentral pressure– State of the tideState of the tide– Configuration of Configuration of

the coastthe coast

• Can exceed 8 m Can exceed 8 m (25’) in worst (25’) in worst case scenariocase scenario

Katrina comes Katrina comes ashoreashore• [Surviving][Surviving]

tide gaugestide gauges

Katrina storm surge (model Katrina storm surge (model hindcast)hindcast)

http://hurricane.lsu.edu/floodprediction/katrina32/images/katrina32.JPG

• It missed It missed New New OrleansOrleans

• Max. Max. impact on impact on Miss. CoastMiss. Coast

• Funneling?Funneling?

Flooding at New OrleansFlooding at New Orleans

• Observed at Observed at Miss. River Miss. River gaugegauge

• Not (quite) Not (quite) to flood to flood stagestage~12 foot ~12 foot storm surgestorm surge

• Big sigh of Big sigh of relief as relief as storm storm passed but…passed but…

Images courtesy NASA

Images courtesy NASA

Images courtesy NASA

Images courtesy NASA

http://coastal.er.usgs.gov/hurricanes/katrina/

•BiloxiBiloxi

•BiloxiBiloxi

•PassPassChristianChristian

Damage (courtesy of USGS)

Most intenseMost intense http://www.nhc.noaa.gov/pastall.shtmlhttp://www.nhc.noaa.gov/pastall.shtml

Rank Hurricane YearCategory

at landfall

MinimumPres. (mb)

MinimumPres.

(in)

1 (FL Keys) 1935 5 892 26.35

2 Camille (MS, SE LA, VA) 1969 5 909 26.84

3 Andrew (SE FL, SE LA) 1992 5 922 27.23

4 (Indianola TX ) 1886 4 925 27.31

5 (FL Keys, S TX) 1919 4 927 27.37

6 (Lake Okeechobee FL) 1928 4 929 27.43

7 Donna (FL, Eastern U.S.) 1960 4 930 27.46

8 (New Orleans LA) 1915 4 931 27.49

8 Carla (N & Cent. TX) 1961 4 931 27.49

10 LA (Last Island) 1856 4 934 27.58

CostliestCostliesthttp://www.nhc.noaa.gov/pastall.shtmlhttp://www.nhc.noaa.gov/pastall.shtml

Rank Hurricane Year Category Damage

1 Andrew (SE FL, SE LA) 1992 5 26.5

2 Charley (SW FL) 2004 4 15

3 Ivan (AL/NW FL) 2004 3 14.2

4 Frances (FL) 2004 2 8.9

5 Hugo (SC) 1989 4 7

6 Jeanne (FL) 2004 3 6.9

7 Allison (N TX) 2001 TS 5

8 Floyd (Mid-Atl & NE) 1999 2 4.5

9 Isabel (Mid-Atlantic) 2003 2 3.4

10 Fran (NC) 1996 3 3.2

Deadliest (through 1996)Deadliest (through 1996)http://www.nhc.noaa.gov/pastall.shtmlhttp://www.nhc.noaa.gov/pastall.shtml

RANKING HURRICANE YEAR CATEGORY DEATHS

1. TX (Galveston) 1900 4 8000+

2. FL (Lake Okeechobee) 1928 4 1836

3. FL (Keys)/S. TX 1919 4 600

4. NEW ENGLAND 1938 3 600

5. FL (Keys) 1935 5 408

6. AUDREY (SW LA/N TX) 1957 4 390

7. NE U.S. 1944 3 390

8. LA (Grand Isle) 1909 4 350

9. LA (New Orleans) 1915 4 275

10. TX (Galveston) 1915 4 275

11. CAMILLE (MS/LA) 1969 5 256

Who’s to blame?Who’s to blame?

• Individuals who assumed risk, then Individuals who assumed risk, then didn’t listen and follow instructionsdidn’t listen and follow instructions

• New Orleans, for not having a real New Orleans, for not having a real evacuation planevacuation plan

• The Corps of Engineers, for a century The Corps of Engineers, for a century and more of false promises and wasted and more of false promises and wasted billionsbillions

• FEMA FEMA et al.et al., for not recognizing the , for not recognizing the scope of the impending disasterscope of the impending disaster

• Congress, for not funding adequate Congress, for not funding adequate maintenance/upgrades of levee systemmaintenance/upgrades of levee system

What do we do about it?What do we do about it?

• Abandon New Orleans?Abandon New Orleans?

• Rebuild New Orleans Rebuild New Orleans onlyonly along the along the natural levees?natural levees?

• Rebuild, but zone/plan undersea areas Rebuild, but zone/plan undersea areas for only unoccupied ground floors?for only unoccupied ground floors?

• Rebuild and raise the levees?Rebuild and raise the levees?

• RebuildRebuild

In summary…In summary…