Residents sought refuge on roofs or the upper floors of their homes, or hiked up the banks to higher ground, he said. One woman had broken her car window as floodwaters rose around it and climbed out onto the top of the vehicle, Mr. Carper said. There were about 800 weather-related calls for help between about 6:30 p.m. and 11 p.m., county figures showed, nearly 130 of which involved reports of high water.
Officials repeatedly issued warnings for people to avoid driving in floods.
In Oakdale Borough, Pa., late on Thursday, emergency workers rescued a woman trapped in a car surrounded by rising waters on Route 51, an 89-mile state highway that runs to the Ohio state line., the authorities said.
Steve Trusnovic, the mayor of Oakdale Borough, said in an email early Friday that two people had been helped out of a vehicle that was stranded in water, and that several other people were given assistance leaving homes and businesses that had become surrounded by flooded streets. There were no reports of injuries or fatalities, he said.
In Washington, Pa., a city of more than 13,000 residents southwest of Pittsburgh, the rain was so relentless that the city declared a state of emergency, calling in a boat from neighboring Peters Township to perform water rescues, the mayor, JoJo Burgess, said on Friday.
One man was rescued from a car as streets and a creek were inundated, he said.
“It was pretty catastrophic,” Mr. Burgess said in an interview. “Everything was flooded. The volume of rain that we got was a danger to the entire region.”
Orlando Mayorquín contributed reporting.