Three people are dead and more than 1,000 were rescued from their homes in Louisiana following what Governor John Bel Edwards described as "unprecedented, historic" rainfall and flooding.
Heavy flood waters swamped not just Louisiana but also southern Mississippi.
Edwards has declared a state of emergency, and national guard soldiers in boats and helicopters have been patrolling southern Louisiana, removing people from their homes where necessary. One town was cut off entirely, and highways were shut down by heavy flood waters.
"This is a major disaster," Edwards said at a news conference on Saturday. "It is an ongoing event."
He added that flooding had already reached record levels, and was spilling out into areas which don't normally get flooded.
Edwards' family are among the evacuees, The Advocate reported. His mansion reportedly has "chest-high water in the basement."
More than 24 inches of rain fell in Livingston, which is part of the Baton Rouge metropolitan area. The flooding was so serious in one Louisiana town that caskets were unearthed from a cemetery. Images posted by the Walker Police Department on Facebook showed at least two yellow caskets floating on the floodwater.
And that's not the last of it. Flash flood warnings are in place in both Louisiana and Mississippi, as weather forecasters warn that the heaviest rain is yet to come, and will make landfall on Saturday afternoon through Sunday.
Follow Tess Owen on Twitter: @misstessowen