Witnesses have been speaking of scenes of devastation after Hurricane Katrina tore through the US Gulf coast - in one case sweeping away a woman sheltering with her husband at their family home.
Harvey Jackson fears his wife died in the storm
One of the worst affected areas appears to be Mississippi's coastal town of Biloxi, where some 30 people were reported to have died at a beachfront apartment complex.
Biloxi resident Harvey Jackson said his wife, Tonette, was missing after surging waters hit their house.
"The house just split in half. We got up the roof and the water came and just opened up, divided," still visibly shaken Mr Jackson told America's ABC television.
"My wife, I can't find her body, she gone."
"I held her hand tight as I could and she told me 'you can't hold me'. She said, 'take care of the kids and the grandkids'," Mr Jackson said.
"We have nowhere to go. I'm lost, that's all I had, that's all I had. I don't know what I'm going to do."
'In rescue mode'
Emergency crews have been working frantically in the affected states to save hundreds of people trapped by floodwaters.
Bryan Vernon spent three hours on his roof after a levee along a canal on the south shore of Lake Pontchartrain gave way.
"I've never encountered anything like it in my life. [The water] just kept rising and rising and rising," Mr Vernon said.
Mississippi Governor Haley Barbour said his worst fear was "that there are a lot of dead people out there".
Biloxi Mayor AJ Holloway described the hurricane as "our tsunami".
"We are still in the search and rescue mode," Mr Holloway told the Biloxi Sun Herald newspaper.
Local rescue crews awaited reinforcements from the federal government and other states to shore up assistance, officials said.
They said it would take days if not weeks before the full impact of the hurricane on the region would be known.