Thousands of homes remain without power in the US Midwest after a huge storm system swept through, killing at least 13 people.
Ten people died in Oklahoma City and its suburbs and three more in Missouri.
Hundreds of people were injured, many of them on roads as they tried to flee tornadoes. Heavy rain has also left many areas flooded.
Two weeks ago a massive tornado struck the Oklahoma City suburb of Moore, killing 24 people.
The National Weather Service's Storm Prediction Centre warned that the severe weather was moving east on Sunday, threatening an area from Virginia to Maine with damaging winds and heavy downpours.
'Lifted off the road'
The Oklahoma Corporation Commission said more than 91,000 homes and businesses were still without power on Saturday. Workers are trying to clear downed lines.
Some 8in (20cm) of rain fell on the Oklahoma City area, causing flash flooding.
A trailer park in Oklahoma City was among the areas evacuated.
Governor Mary Fallin insisted: "We're going to get through this."
The storm struck in the rush hour on Friday night, with many people taking to the roads to try to get to safer areas.
Terri Black, a teacher's assistant in Moore, told Associated Press she had tried to outrun a predicted tornado: "It was chaos. People were going southbound in the northbound lanes. Everybody was running for their lives.
"My car was actually lifted off the road and then set back down."
Two of those who died, a mother and her baby, were sucked out of their car when the largest tornado of the storm struck near the Oklahoma town of El Reno.
The tornado ripped down the highway, overturning cars and lorries.
Amy Elliott, a spokeswoman for the Oklahoma medical examiner's office, confirmed two children and seven adults had died in the state.
Scott Holste, a spokesman for Missouri Governor Jay Nixon, said three people had died in flooding in that state.
Violent winds overturned vehicles on Interstate 70 between St Louis and St Charles County.
Mr Nixon toured affected areas and urged residents to avoid flooded regions.
"Missouri has been hit by several rounds of severe storms in the past few weeks," he said.
"Because many streams and rivers are overflowing their banks, we will need to stay vigilant in both monitoring and responding to flooding across the state as well. This remains a dangerous situation."
In Iowa, Governor Terry Branstad issued a disaster proclamation for several flooded counties.
A school in Gillespie, Illinois, had its roof torn off by a tornado packing 115mph (185km/h) winds.
Meteorologists said the tornadoes were less severe than the one that struck Moore two weeks ago.
That tornado - ranked as an EF5, the most powerful - destroyed some 1,200 homes. About 33,000 people were affected and the damage has been estimated at $2bn (£1.32bn).
Oklahoma is in part of the US Midwest known as Tornado Alley. Some 1,200 tornadoes strike each year, though most are relatively small.