Hurricane Isaac contributed to a moist air mass that brought torrential rainfall and street flooding Tuesday in Charleston, South Carolina, officials said.
By evening, between 4 and 8 inches had fallen across the low-lying metropolitan area.
"We were stranded and had to be rescued ourselves," said Charleston County spokeswoman Tracey Amick. "Our car had water coming through the doors. It's ridiculous right now. There are trash cans floating down the street, cars stuck, people trying to get through these flooded streets on bicycles."
The tropical moisture, combined with a trough of low pressure off the coast, prompted a flash-flood warning in the city that was to continue until 12:30 a.m. Wednesday.
About 20 vehicles were stranded on streets at one time, said meteorologist Vern Beaver of the National Weather Service. Heavy flooding also was reported in Mount Pleasant and North Charleston.
The College of Charleston reported 5 inches of rainfall by 7 p.m. Tuesday. West Ashley reported 7.5 inches, as did Daniel Island.
Significant flooding was reported near the Historic Charleston City Market.
The worst of the flooding appeared over late Tuesday, forecasters said.
Senior forecaster Steven Taylor said most of the rain Tuesday afternoon fell during low tide. Winds were pushing slightly above normal tides in downtown Charleston.
"If we get heavy rain to fall during high tide, the flooding level will only increase," he said.
Beaver expected rain to continue into Thursday, although it won't be as heavy as Tuesday's downpour.