In New Orleans, the Coast Guard said Tuesday it rescued some 1,500 people.
Mayor Ray Nagin said hundreds, if not thousands, of people may still be stuck on roofs and in attics, and so rescue boats were bypassing the dead in favor of the living.
Here are stories of a few of those rescues.
Frank Mills was in a boarding house with three elderly residents when water started swirling up to the ceiling.
Mills, 56, made for the front door but an elderly man went to a bedroom to retrieve something, and a woman went to help him.
"And when I saw her in the hallway, she was floating face up," Mills said. He said he never saw the other man again.
Mills said he made it to a roof covering the front porch of the one-story house in the lower Ninth Ward section and tried to pull another elderly man to safety. But he slipped away, Mills said.
"He was kind of on the edge of the roof, catching his breath," Mills said. "Next thing I knew he came floating past me. ... I don't know if he drowned or had a heart attack."
Mills sat on the roof for about two hours before catching a floating compressor in the 20-foot-deep water and making his way to a two-story building nearby, where he was eventually picked up by a boat.
"I was next, that's what I was thinking," a barefoot Mills said as he stood in line at the Superdome with nothing but a ruined Walkman, a soaked cell phone and a bottle of water in a garbage bag.
"Y'all want a ride?" Sgt. Aaron Monceaux called out cheerfully, gliding his boat over the roof of a car and knocking with his fist on the upper corner of a nearly submerged door.
A curtain parted, and a woman's face appeared at the window.
She disappeared inside the flooded house to gather a laundry bag of possessions, then Monceaux, an officer with the Louisiana Department of Wildlife and Fisheries, gently helped her into his boat.
"I just didn't want to leave out of my house," said Donna Webber, 47. "I'm just devastated. I didn't want to lose all of my furniture."
The rescue boats worked the city all afternoon. The rescuers called to each other, giving advice, directions, pointers about where to look for the next passengers.
Off one street, Monceaux pulled his skiff up to what had been a trim, pastel-green cottage. Frightened residents were looking out from a second-story balcony. They had been trying to get help since the evening before.
The wildlife officer gingerly lowered a woman into his boat from the balcony, and the craft listed uneasily, scaring the woman who said she didn't know how to swim.
Mary Stewart, 80, slid off the back of a National Guard truck with nothing but the clothes on her back, her purse and the shoe on her left foot.
"I was so scared I don't feel I have any entrails anymore," said Stewart, who spent a harrowing night in the attic of a beauty salon in the city's flooded Ninth Ward.
Beauty salon employee Kioka Williams, 23, said they had to hack through the ceiling to reach the attic as the water rose.
"Oh my God, it was hell," she said. "We were screaming, hollering, flashing lights. It was complete chaos."
The eight people in the salon were rescued early Tuesday by a police boat.
"I almost died in the night water," Willie Anderson, 49, said as he arrived at the Superdome. He had spent the night in his attic in the inundated Ninth Ward.
Even those who fled New Orleans had trouble. Sixteen-year-old Shakia Cooper and her family left New Orleans on Sunday and checked into a Day's Inn near Interstate 10. They thought they would be safe. Then came the rain ... and labor pains.
Her mother, Lisa Cooper, called 911, but was told rescuers couldn't reach the flooded hotel. A nurse who was staying there helped deliver the baby while the nurse's husband waded through the water to reach National Guardsmen on the highway.
"They came and got us in a boat," said the elder Cooper, who accompanied her daughter and the newborn boy to Ochsner after the birth early Tuesday morning.