The city of New Orleans is in a state of devastation," Nagin told WWL TV on Monday night. "We probably have 80 percent of our city underwater, with some sections of our city, the water is as deep as 20 feet."

Bryan Vernon, who lives in the neighborhood, told The Associated Press he had been on his roof for three hours calling for someone to help him and his fiancee from the rising water. (Watch dramatic rooftop rescue) "I've never encountered anything like it in my life," Vernon told AP. "It just kept rising and rising and rising." Along a street that had turned into a river filled with garbage cans and refuse, a woman leaned from the second-story window of a brick home and begged to be rescued, AP reported. "There are three kids in here," the woman told AP. "Can you help us?"

In New Orleans' central business district, Karen Troyer Caraway, vice president of Tulane University Hospital, said water at the facility was initially rising at the rate of a foot an hour and had already reached the top of the first floor. "It's dumping all the lake water in Orleans Parish," Caraway said. "It's essentially running down Canal Street. We have whitecaps on Canal Street." "We now are completely surrounded by 6 feet of water, and are about to get on the phone with FEMA to start talking about evacuation plans," Caraway said. "The water is rising so fast, I can't even begin to describe how fast it is rising." Caraway said she didn't know whether any pumps had been turned on to pump the water, but said, "they're not going to be able to compete with Lake Pontchartrain." Tulane hospital has moved its emergency room to the second floor, Caraway said. It has been on emergency generator power for the last 24 hours, but if water continued rising rapidly, that power will be lost, swamping the power source.