Gustav: Cat 3 Winds and Surge Expected

Posted on September 1, 2008

A NOAA graphic shows the surface wind field of Hurricane Gustav. You can see a large version of this graphic here. The strongest winds are generally on the right side of the hurricane. After Gustav makes landfall the wind field will expand outward but the storm will also start to weaken. The NHC expects Hurricane Gustav to make landfall with winds near 115 mph.

The winds are bad enough but it is the surge that New Orleans and residents living on the coast should be the most concerned with. It remains to be seen whether the New Orleans levees will be able to survive the surge of Hurricane Gustav. Dr. Jeff Masters blogged yesterday that the levee system of New Orleans was built to withstand a Cat 3 storm surge.

The levee system of New Orleans is designed to withstand a Category 3 storm surge. If Gustav intensifies more than the NHC forecast is calling for, there is a significant threat of multiple levee failures in the New Orleans levee system resulting in flooding of portions of the city. However, the latest 12Z (8 am EDT) model runs have shifted their landfall points a bit further west, reducing the odds of a Category 4 storm surge in New Orleans. My best guess is that New Orleans will suffer a Category 2 or 3-level storm surge. The levees will hold with that level of storm surge, if they perform as designed.

You can see a computer estimated surge map here. Hurricane Gustav will definitely be a huge test for the levee system of New Orleans - hopefully it will perform as designed.

The NHC is also concerned with flooding because Gustav is expected to slow to crawl somewhere over East Texas. As we saw with Tropical Storm Fay inland flooding can be a very serious problem. You can see precipitation estimates here from the Hydrometeorological Prediction Center.