Tornadoes and storms that struck the eastern United States killed at least 36 people and injured many others.
The National Weather Service Storm Prediction Center said it had early reports of 72 tornadoes in 12 states through to yesterday.
Tennessee was hardest hit, with 17 confirmed deaths from storms. Some of the most severe damage occurred in mountainous eastern Tennessee near Knoxville, where much of the tiny mountain town of Mossy Grove was flattened.
There also were 12 deaths in Alabama, five in Ohio, one in Mississippi and another in Pennsylvania, where a man died in the collapse of a home near Pittsburgh during a storm that apparently was not a tornado.
In Mossy Grove, survivors told of pulling mattresses off their beds, and cowering under them as the storms swept in.
"The whole sky was lit up," said one witnesss. "You could see down the road. You could see the twister, a big black funnel cloud," she said from a shelter at the Calvary Baptist Church in Wartburg, Tennessee.