This article is so close that it's shocking:
It was a broiling August afternoon in New Orleans, Louisiana, the Big Easy, the City That Care Forgot. Those who ventured outside moved as if they were swimming in tupelo honey. Those inside paid silent homage to the man who invented air-conditioning as they watched TV "storm teams" warn of a hurricane in the Gulf of Mexico. Nothing surprising there: Hurricanes in August are as much a part of life in this town as hangovers on Ash Wednesday.Nearly 80 percent of New Orleans lies below sea level—more than eight feet below in places—so the water poured in.people climbed onto roofs to escape it.Thousands more who survived the flood later perished from dehydration and disease as they waited to be rescued. It took two months to pump the city dry, and by then the Big Easy was buried under a blanket of putrid sediment, a million people were homeless,Read the whole article here: http://www3.nationalgeographic.com/ngm/0410/feature5/When did this calamity happen? It hasn't—yet. But the doomsday scenario is not far-fetched.