Eighteen people have been killed after heavy rain in West Virginia destroyed or seriously damaged more than 100 homes and left tens of thousands without power.
About 500 people were stranded overnight in a shopping centre when a bridge was washed away, and dozens of other people had to be plucked off rooftops or rescued as waters quickly rose during the storm.
"Our focus remains on search and rescue," governor Earl Ray Tomblin said.
He added: "It's been a long 24 hours and the next 24 hours may not be much easier."
The deaths included an eight-year-old boy and a four-year-old boy who were swept away in different counties, authorities said.
Greenbrier County Sheriff Jan Cahill described "complete chaos" in his county, which was one of the hardest hit.
"Roads destroyed, bridges out, homes burned down, washed off foundations," he said. "Multiple sections of highway just missing. Pavement just peeled off like a banana. I've never seen anything like that."
Water rescue teams were searching devastated areas.
"Today's just an accountability mission, trying to verify where everybody's at and follow up on missing person tips," he said. "It's really hard to navigate around because there's just a ton of debris. We've even had rescuers that had to be rescued."
The rain submerged homes and cars in dirty brown water and chewed up roads.
Some areas are "probably looking at flooding that's going to be the worst in 100 years," the governor's spokesman Chris Stadelman said.
Eric Blackshire was one of the stranded at Crossings Mall, a mix of restaurants, stores and a hotel in Elkview, which is about 15 miles north east of Charleston. Some had to sleep in their cars or at businesses overnight. Mr Blackshire opted for a hotel room.
"It was kind of like a hurricane party. I guess you could call it a flood party. There were lots of beers being drank last night," he said.
He was able to get to safety on Friday when Pinch Volunteer Fire Department firefighters used a rope to guide people down a hillside. About 50 people have been rescued so far.
An area near the West Virginia-Virginia border received at least 9 inches of rain while other parts of the state had 3 to 5 inches, National Weather Service hydrologist John Sikora said. While most of the rain had passed on Friday, there were still scattered showers, thunderstorms and river flood warnings.
Kanawha County officials reported at least 70 water rescues. The Republican governor said rescue workers have risked their own lives to rescue people stranded on rooftops and in overflowing rivers. In Richwood, state police and local responders rescued a woman trapped in her car with water rising up to her neck, he said.