The devastating impact of hurricanes on lives and property is well-known and experienced by many. But the impact of hurricanes on the environment is less well known, and in many cases, undocumented. Extreme winds, flooding rains, pounding waves, and storm surges that overrun the shore all contribute to the impacts that a tropical cyclone can have on coastal and marine environments.

At 6:10 am, on August 29, 2005, Hurricane Katrina made it’s second landfall on a US coast. Katrina had made it’s first landfall as a Category 1 storm on the evening of August 25 near the Dade and Broward county lines in south Florida. After crossing the lower Florida peninsula and entering the Gulf of Mexico, the storm regained strength. Moving west then northwest across the Gulf, the storm strengthened to Category 5, with maximum sustained winds of 175 mph and a minimum central pressure of 902 mb. Before reaching the Louisiana coast, Katrina weakened slightly to Category 4, with 140 mph winds. A massive storm surge blasted small river delta towns, lifted ships onto land, and inundated coastal marshes with a mix of seawater, crude oil, and debris.

Biologists and environmental scientists have been unable to reach coastal areas of extreme southeastern Louisiana since Katrina’s landfall, in part because many of them have been involved in relief efforts in hurricane-flooded New Orleans. But the storm itself has blocked access to many Mississippi River delta communities– many areas in the delta remain flooded two weeks after the storm’s crossing, roads are washed out, and many waterways are not yet navigable due to missing channel markers and sunken vessels. However, preliminary reports from the delta indicate that Katrina has negatively impacted the environment. Aerial and satellite photos have shown at least two major oil spills in the delta, extreme erosion on barrier islands, and saltwater intrusion in delta marshes. Coastal fisherman report oyster beds are covered with mud, local waters are devoid of shrimp and fish, and herds of cattle were dead.

While assessments are just beginning, many experts believe that it will take years for Louisiana’s coastal environment to recover from Katrina’s impact.