At least 291 people were killed across six states - more than two-thirds of them in Alabama - as America's deadliest tornado outbreak in almost four decades pulverised entire neighbourhoods.
Firefighters searched one splintered pile after another for survivors, combing the remains of houses and neighbourhoods of large large cities that bore the half-mile-wide scars the twisters left behind.
President Barack Obama, travelling to Alabama to see the storm damage and talk to affected families, has signed a disaster declaration for the state to help residents clean up the devastation.
"We can't control when or where a terrible storm may strike, but we can control how we respond to it," Mr Obama said. "And I want every American who has been affected by this disaster to know that the federal government will do everything we can to help you recover and we will stand with you as you rebuild."
The death toll from Wednesday's storms seemed from a bygone era, before Doppler radar and pinpoint satellite forecasts were around to warn communities of severe weather.
Residents were told the tornadoes were coming up to 24 minutes ahead of time, but they were just too wide, too powerful and too locked on to populated areas to avoid a horrifying body count.
"These were the most intense super-cell thunderstorms that I think anybody who was out there forecasting has ever seen," said meteorologist Greg Carbin at the National Weather Service's Storm Prediction Centre in Norman, Oklahoma. "If you experienced a direct hit from one of these, you'd have to be in a reinforced room, storm shelter or underground" to survive, he said.
The storms seemed to hug the interstate highways as they barrelled along like runaway trucks, obliterating neighbourhoods or even entire towns from Tuscaloosa to Virginia.
Search and rescue teams fanned out to dig through the rubble of devastated communities that bore eerie similarities to the Gulf Coast after Hurricane Katrina in 2005, when town after town lay flattened for nearly 90 miles.
The storm prediction centre said it received 164 tornado reports around the region, but some tornadoes were probably reported multiple times and it could take days to get a final count.