The weather service and state officials said that in addition to the 31 killed in Tennessee, there were 13 dead in Arkansas, seven in Kentucky and four in Alabama. Injuries were widespread, with 149 people hurt in Tennessee alone.
"We know of eight dead and are still looking," said Shelvy Linville, mayor of Lafayette, Tennessee. "There's a lot of devastation."
Power outages were widespread. One tornado struck the Columbia Gulf Transmission company in Hartsville, Tennessee, and set off a natural gas fire that lit up the early morning sky, officials said.
Kentucky Gov. Steve Beshear described to CNN a trail of devastation in his state seen from the air.
"In the path of it there is nothing left and on either side of it things are standing just like nothing has happened. It's an amazing picture to see."
Inspection of the damage began midmorning on Wednesday, with the last tornado reported a few hours earlier in Jackson County, northeastern Alabama, the weather service said. Late in the day, forecasters said there was no longer a threat of severe weather across the region.
In Alabama, Tina Johnson, 41, of Pinhook, said she watched from her house as a tornado tore apart her barn.
"The lightning and rain started back up suddenly and then we could see the funnel cloud through the lightning," she said. "The preacher's brick house across the street was destroyed and a mobile home nearby was nothing but a few pieces of tin."
Kentucky National Guard spokesman David Altom said about 50 soldiers were deployed and others on stand-by. "The mission right now is to protect the damaged homes from looting," he said.
Mississippi reported no deaths but about 11 injuries after two tornadoes ripped across an industrial park, seriously damaging a Caterpillar factory, and farm communities north of the University of Mississippi campus in Oxford.
In Jackson, Tennessee, a tornado damaged most of the student housing at Union University, injuring more than 50 students, although none of the injuries was life-threatening. It was the third time in less than a decade a twister struck the school.
