Hurricane Gustav Update: September 4, 2008

Hurricane Gustav primarily damaged barrier islands when it hit the Louisiana coast Sept. 1 as a category 2 hurricane, according to scientists from the U.S. Geological Survey’s National Wetlands Research Center in Lafayette, La.

Biologists and geographers flew the Louisiana coast Sept. 4, collecting post-storm video photography to compare with pre-storm photography they collected the week before. Post-storm video of land between Raccoon Island and Grand Isle will be available at this site on Sept. 5. Center scientists also flew the coast with the U.S. Fish and Wildlife Service and collected digital photography.

Tommy Michot, USGS biologist who has flown the Louisiana coast for decades, said, “It looks like most of the structural landscape damage was to barrier islands like Raccoon Island, which lost about a third of its area. The area was mostly low and unvegetated before the storm. But it will take months before a full wetland assessment can be completed. USGS will be acquiring coastwide photography and satellite imagery this fall to assist in long-term monitoring.”

Geographer Chris Wells also observed marsh erosion on the coast.

The wetlands center is also cooperating with the USGS Water Science Center in Baton Rouge to correlate vegetation damage with storm surge and wind speed data (http://www.usgs.gov/state/state.asp?State=LA).

Pre-storm photography in southeast Louisiana’s deltaic plain includes images of areas directly impacted by the eye of the storm such as Grand Isle and the Isles Dernieres Barrier Island chain. Other southeastern locations covered include the Mississippi River Delta, the Chandeleur Barrier Island chain, the Pearl River Wildlife Management Area, and the Jean Lafitte National Historical Park and Preserve. Comparison of pre- and post-storm photography from southwest Louisiana will follow.

Scientists do not anticipate the damages to coastal lands will be as severe as what was seen after Hurricanes Katrina and Rita in 2005.

Wetlands and coastal marshes are natural buffers from storm surge and hurricane force winds. NWRC has been monitoring wetland changes in Louisiana since 1976. Some of the changes due to Hurricanes Katrina and Rita are documented in the USGS publication, Science and the Storms: the USGS Response to the Hurricanes of 2005.

Coastal Louisiana had lost more than 1900 square miles of coastal land since the 1930s. The center calculated that Hurricanes Katrina and Rita caused the loss of an additional 217 square miles of coastal wetlands to open water in 2005. In 2006, the center determined that only about 19 square miles of coastal wetlands had been recovered. The center will continue to determine wetland change based on the analysis of satellite data, aerial photography and ground observation.

The center also deployed its Science Response Vehicle to Baton Rouge after Hurricane Gustav to assist center staff and partners in Baton Rouge with spatial analysis of hurricane damage to wetlands. The SRV is used for rapid deployment in response to natural disasters. It is equipped with computers, software, and plotters to assist in data analysis using geospatial information systems. The vehicle's equipment was used after Hurricanes Katrina and Rita to help with mapping critical infrastructure for first responders, mapping 911 calls, and transferring critical data to various agencies.