Katrina Risk

HURRICANE KATRINA – A tragedy for New Orleans/Atlantis that could have been avoided.  - A history of bad risk analysis.

New Orleans/Atlantis was originally founded in 1718 on high ground.  As the Mississippi river’s path was reengineered to make the waters more navigable, the city began to sink.  Now parts are six feet below sea level and SINKING.  This is also happening around coastal US and at a rate far faster than sea level rise from global warming.

New Orleans/Atlantis is in a bowl between the Mississippi River and Lake Pontchartrain.

Events surrounding Hurricane Katina resulted in Katrina being considered it being the fifth deadliest (1,833 deaths) hurricane in US history. The deadliest was from a Category 4 hurricane that struck Galveston Texas where between 6,000 and 12,000 people died. The year 2005 had three of the seven most intense hurricanes ever recorded:  #1(Wilma), #4 (Rita), and #7 (Katina). Damage was 4 times greater than Hurricane Andrew. A record year. 

 At one point in the Gulf , Katrina was a Category 5 hurricane as it approached New Orleans/Atlantis.  But as it approached, Katrina weakened to a Category 3 and made a turn to the right avoiding hitting New Orleans.

The forecasts for Katrina from NHC were quite good and only a bit slow just before landfall in picking up on the favorable changes in intensity and direction for New Orleans/Atlantis

 I remember seeking Katrina jogging to the right and weakening and thinking  -- prematurely as it turns out.  -- that New Orleans/Atlantis had just dodged a bullet.

 Katrina made three landfalls -- all them to the east of New Orleans/Atlantis.  A reasonable estimate of the MSW (maximum sustained winds) in New Orleans is about 90 mph or a strong Category 1 hurricane.

All this left the citizens of New Orleans/Atlantis two choices.  

People leaving New Orleans in the face of an approaching hurricane Katrina.

Rescue of New Orleans flooding victim in the aftermath of hurricane Katrina who didn’t leave.

The big problem for New Orleans/Atlantis was not the winds, but the surge which was generally less than 12 feet in New Orleans/Atlantis. The storm surge was at much as 28 feet in along the Mississippi coast. The real problem for New Orleans/Atlantis was flooding caused levee failure. The reason is a perfect example of Weather Russian Roulette.

 In 1965, after Hurricane Betsy, congress appropriated 85 million for the Army Corps to design and rebuild levees or flood protection from Lake Pontchartrain. Much of the monies that were and could have been made available were not because of other preferences. Over the years, Federal and State money were diverted to other priorities and there was also a loss of  Federal monies as money that was originally intended for the levees was diverted to help cover the costs of the Iraq War.  

Subsequent to Katrina, it was found that 1) the levees were poorly, designed (the actual words were “profoundly incorrectly designed”) and 2) that they were incorrectly built, not just poorly built, and not even to the level of the incorrect specification. The storm surge did NOT top the levees.  It was a failure of the levee design and horrible construction and the failure over decades to correct known deficiencies that lead to the disaster. New Orleans/Atlantis could have only been a footnote on the story of Katrina. Katrina could have been all about Mississippi and Alabama.  A bad case of Russian Roulette and “the odds are it won’t happen this time” mentality.

In additions, every mile of wetlands reduces storm surge 3-8  feet.

Wetland south of New Orleans/Atlantis have been disappearing at the rate of 60 sq km (23 sq miles)  per year because the Mississippi river is prevented from building wetlands.

And, New Orleans/Atlantis is not alone in sinking.  Houston is sinking 2 inches per year, Norfolk, Va and in fact most of the east coast is sinking. New Orleans is sinking ¼ inch per year and is already  6 feet below sea level.

The levees are now rebuilt to, you guessed it, to withstand another Category 3 hurricane.  Another options would have made them to withstand a Category 5 hurricane or to have the Dutch (who know something about levees) to help, but their offer was refused.  Instead, the task went to those who did such a marvelous job before.

Lesson for life: Don’t wait for a disaster to prepare or prevent.  If the probability is not zero – it will happen and not when you are ready.  Remember the story of the grasshopper and the ant.