At least one man is believed dead as Tropical Storm Isaac spun tornadoes across Mississippi and Alabama on Thursday, causing flooding across the states, but New Orleans' flood defences appear to be holding firm.
ABC News reported a truck driver was killed by a tree that fell, in heavy wind and driving rain, at around midnight on Wednesday night in Pearl River County, Mississippi. His name has not been released.
The area's emergency management department warned that the worse was yet to come for the flooded county.
Thousands of people to the north and south of the city, including 3,000 from Lake Ponchartrain, had to be evacuated or rescued as the storm lashed the Gulf Coast, now heading inland towards Arkansas.
Louisiana is expected to see two feet of rain, causing devastating flooding, through to the weekend.
The storm arrived exactly seven years after Hurricane Katrina killed 1,800 people in Louisiana and Mississippi, but the damage is expected to be much less serious.
Mid-afternoon on Wednesday, Isaac was downgraded to a tropical storm with winds decreased to 45mph and the National Hurricane Centre said it was expected to become a tropical depression by Thursday night, meaning its top winds would drop below 39mph.
The storm knocked out power to as many as 700,000 people, stripped branches off trees and flattened fields of sugar cane, according to the Associated Press.
Surrounding areas of Louisiana are expected to see almost two feet of rain and more dangerous floods by the end of the week, while eight tornadoes have reportedly spun off from Isaac in Mississippi and Alabama in the past 24 hours.
The Louisiana National Guard ceased rescue operations in Plaquemines Parish, and said it believed no residents remained in their homes. More than 100 nursing home residents were evacuated.
Romaine Dahl, 59, told AP: "I don't think we had to evacuate to begin with. The weather was a hell of a lot worse last night than it is now."