Tuesday, August 28, 2012
A look at Gustav (2008)
Hurricane Gustav entered the Gulf of Mexico as a category-3 hurricane, then weakened into a category-2 storm before making landfall in South Louisiana. The highest surge levels were located to the east of the Mississippi River, in places like Bay Gardene, Shell Beach, and even along the Mississippi Coast. Northeast Bay Gardene, LA, observed the highest water levels, with a storm surge of 12.5 feet and storm tide of 13.63 feet.
Note that Gustav tracked to the west of the Mississippi River, but the peak surges occurred on east side of river. Even portions of the Mississippi Coast observed surge levels greater than 8 feet, which were higher than locations closer to the point of landfall. This is an example of how effectively water piles up on the eastern levees of Plaquemines Parish, in eastern communities of St. Bernard Parish, such as Shell Beach, and in the Mississippi Sound.
Isaac is different than Gustav in several ways- it has a broader wind field but is less intense, and the latest forecasts suggest it will track farther east than Gustav. However, it may be helpful to look at these observed water levels for context. In the previous blog, I posted a similar map for Hurricane Georges (1998). The NHC forecast map places Isaac's track somewhere between these two systems, but most likely with less intensity. Even if Isaac is quite different than these storms, in terms of size, intensity and exact track/ point of landfall, it may be helpful to gain familiarity with surge patterns seen in these storms that approached LA from the southeast.