FRANKFORT, Ky. — The rain that unleashed massive floods in Appalachian mountain communities was diminishing on Tuesday, leaving survivors to face a new threat: baking in the heat as they try to recover.

“It’s going to get really, really hot. And that is now our new weather challenge,” Kentucky Gov. Andy Beshear said at his morning briefing on the disaster.

The death toll stood at 37 on Tuesday after more bodies were found Monday in the ruined landscape, and while more than 1,300 people have been rescued, crews are still trying to reach some people who remain cut off by floods or mudslides. Hundreds were unaccounted for, a number that should drop as cellphone service is restored and people can tell each other they’re alive, the governor said.

“It is absolutely devastating out there,” Beshear said. “It’s going to take years to rebuild. People left with absolutely nothing. Homes that we don’t know where they are, just entirely gone. And we continue to find bodies of our brothers and sisters that we have lost.”

The National Weather Service warned that slow-moving showers and thunderstorms could provoke more flash flooding through Tuesday morning along waterways swollen by Sunday’s heavy rain, a dismal coda to last week’s historic floods. That includes communities just across the state line in Virginia and West Virginia, where some people also remain without power.

Cooling stations are being set up in buildings that were spared the floods as more than 9,600 customers remain without electricity in eastern Kentucky, Beshear said.

“They have been set up in time, in fact before this heat. We may, for the first time, be ahead of the weather,” he said.

“I know you may be out there working to salvage whatever you can. But be really careful Wednesday and Thursday when it gets hot,” the governor said. “We’re bringing in water by the truckloads. We’re going to make sure we have enough for you. But you’re going to need a cool place at least to take a break.”

For hundreds of people whose homes were damaged or destroyed, that place was an emergency shelter. As of Tuesday, nearly 430 people were staying at 11 such shelters, and 191 more were being housed temporarily in state parks, Beshear said.

Meanwhile, the flooding has forced some eastern Kentucky districts to delay the start of school. Several schools in the region were damaged, officials said, and the focus now is on helping families whose homes were damaged or destroyed.

“Just that in and of itself is going to take time before we can even start the conversation with the community about where kids are going to go to school,” said John Jett, superintendent in Perry County, where classes were supposed to start Aug. 11 but have been delayed.

Two of the Perry County district’s nine schools suffered severe damage and one will likely have to be rebuilt because of a partial collapse, he said.

In Knott County, Superintendent Brent Hoover said classes would be delayed until the district can assess damage at the high school, an elementary school and the technology center. In Letcher County, Superintendent Denise Yonts said six of the district’s 10 schools were damaged by flooding and two staff members died. The district is committed to getting students back into classrooms as soon as possible to restore some sense of normalcy, she said.

“Our community as a whole is devastated,” Yonts said.

President Joe Biden declared a federal disaster to direct relief money to counties flooded after 8 to 10 1/2 inches (20 to 27 centimeters) of rain fell in just 48 hours in parts of eastern Kentucky, southern West Virginia and western Virginia.

The disaster was the latest in a string of catastrophic deluges that have pounded parts of the U.S. this summer, including St. Louis. Scientists warn that climate change is making such events more common.