not evacuate. there were papers written about just such a scenerio and yet they act ignorant about it. This article was written a year before this happened.
http://magma.nationalgeographic.com/ngm/0410/feature5/But the next day the storm gathered steam and drew a bead on the city. As the whirling maelstrom approached the coast, more than a million people evacuated to higher ground.
Some 200,000 remained, however—the car-less, the homeless, the aged and infirm, and those die-hard New Orleanians who look for any excuse to throw a party. The storm hit Breton Sound with the fury of a nuclear warhead, pushing a deadly storm surge into Lake Pontchartrain. The water crept to the top of the massive berm that holds back the lake and then spilled over. Nearly 80 percent of New Orleans lies below sea level—more than eight feet below in places—so the water poured in. A liquid brown wall washed over the brick ranch homes of Gentilly, over the clapboard houses of the Ninth Ward, over the white-columned porches of the Garden District, until it raced through the bars and strip joints on Bourbon Street like the pale rider of the Apocalypse. As it reached 25 feet (eight meters) over parts of the city, people climbed onto roofs to escape it.
When did this calamity happen? It hasn't—yet. But the doomsday scenario is not far-fetched. The Federal Emergency Management Agency lists a hurricane strike on New Orleans as one of the most dire threats to the nation, up there with a large earthquake in California or a terrorist attack on New York City. Even the Red Cross no longer opens hurricane shelters in the city, claiming the risk to its workers is too great.
"The killer for Louisiana is a Category Three storm at 72 hours before landfall that becomes a Category Four at 48 hours and a Category Five at 24 hours—coming from the worst direction," says Joe Suhayda, a retired coastal engineer at Louisiana State University who has spent 30 years studying the coast. Suhayda is sitting in a lakefront restaurant on an actual August afternoon sipping lemonade and talking about the chinks in the city's hurricane armor. "I don't think people realize how precarious we are,"
Suhayda says, watching sailboats glide by. "Our technology is great when it works. But when it fails, it's going to make things much worse."
The chances of such a storm hitting New Orleans in any given year are slight, but the danger is growing. Climatologists predict that powerful storms may occur more frequently this century, while rising sea level from global warming is putting low-lying coasts at greater risk.
"It's not if it will happen," says University of New Orleans geologist Shea Penland. "It's when."