Courtesy of the U.S. Geological Survey Gone With the WavesA latticework of narrow beaches, sand flats, dunes, and marshes southeast of New Orleans, Louisiana’s Chandeleur Islands (seen at top in July 2001) were largely submerged by Hurricane Katrina’s powerful storm surge, pictured at bottom on August 31, 2005.Within days the surge stripped sand from beaches and ate away large sections of marsh from the island chain, leaving few recognizable landforms in its wake, according to the U.S. Geological Survey.Today the Chandeleur Islands are in hot water again due to the Gulf of Mexico’s Deepwater Horizon oil spill, which coated many of the area’s shorebirds with oil.Ng Staff/National Geographic StockSource: http://news.nationalgeographic.com/news/2010/08/photogalleries/100826-hurricane-katrina-pictures-fifth-anniversary-nation-before-after/