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]