Thursday, December 08, 2005

Return periods for Hurricane Katrina

Hurricane Katrina is the most destructive natural disaster in U.S. history. The relative infrequency of severe coastal hurricanes implies that empirical probability estimates of the next big one will be unreliable. Here we use an extreme-value model and show that a hurricane of Katrina's intensity or stronger can be expected to occur, on average, once every 21 years somewhere along the Gulf coast and once every 14 years somewhere along the entire coast from Texas to Maine. The model predicts a 100-year return level of 83 m/s (186 mph) during globally warm years and 75 m/s (168 mph) during globally cool years. The magnitude of this difference is consistent with models predicting an increase in hurricane intensity with increasing greenhouse warming.

[with T.H. Jagger & A.A. Tsonis]

2 comments:

Jay R said...

Dr. Elsner,

How is this 21 year return period compatible with Dr. Liu's (and others) paleotempistology work ? A catastrophic event like Katrina is estimated to occur every 300 years.

Also, specifically, for Louisiana/Miss coast ? If it is 21 years, why has a similar storm not been experienced over the past 100 years ?

Which model are you using to make you predictions ?

James Elsner said...

Jay,
The 21 year return period refers to the coastal section from Brownsville TX to Mobile AL and thus covers a much larger region that what Dr Liu is looking at. For any one location (e.g., New Orleans) the return period of a Katrina-like storm will be much longer. There have been 4-5 Katrina like storms in this region over the past 100 years including Camille, Carla, etc. I hope this helps.
Jim