Dozens of motorists were stranded in standing water Wednesday as heavy rain fell across the region, causing scores of road closures and concern from officials that with the downpour expected to continue overnight, conditions could worsen Thursday.

No serious injuries were reported, but officials lamented that many drivers had ignored warnings not to drive on flooded streets.

The problem appeared to be worst in Montgomery County, where as of 7:15 p.m. firefighters had rescued motorists from more than 20 cars trapped in rising waters. Five drivers were saved by firefighters in Fairfax County. In Loudoun County, a man was rescued by boat from the roof of his propane truck. And in Bowie, a raft was used to retrieve a driver trapped in his Range Rover.

At one point, firefighters rescued a driver and a dog from a Maserati that was stuck in water on the Cabin John Parkway, said Pete Piringer, a spokesman for Montgomery County’s Fire and Rescue Service.

In Baltimore, a street collapsed in the Charles Village neighborhood, washing away cars and flooding CSX railroad tracks that run below street level. Ian Brennan, a spokesman for the Baltimore City fire department, said no injuries were reported.

Social media users in Florida and North Carolina posted videos of the extreme flooding in their neighborhoods. (Nicki DeMarco/The Washington Post)

The neighborhood is largely residential rowhouses. Brennan said no houses were damaged, but fire officials said many residents living along East 26th Street were ordered to leave until building inspectors could assess their properties.

In Montgomery near the Patuxent River and the Howard County line, a woman called 911 just after 8 p.m. and said she was stranded in her car.

As rescuers drove to the site, they were slowed by flooded roads and soon were told that the driver had fallen from her vehicle into rushing water, Piringer said.

Rescuers deployed two boats and took about 20 minutes to find the woman and bring her to shore, Piringer said. The woman suffered injuries that were not considered to be life-threatening.

“The waves of downpour were pretty intense; visibility was reduced” for drivers, Piringer said earlier. For those who were stranded, “it was pretty treacherous and dramatic.”

In Fairfax, emergency crews descended Wednesday night on the Huntington area, which has a history of flooding.

“We were over there knocking on doors, and we were concerned, but, thankfully, other than street flooding, we believe the scenario of flooding has passed for that neighborhood,” said Tony Castrilli, a spokesman for the county.

Fairfax closed about 25 roads throughout the day and made two swift-water rescues in the Chantilly and Centreville areas, officials said.

In Old Town Alexandria, flooding forced officials to close the Strand between Prince and King streets and at the east end of Prince Street. As of 9 p.m., water covered Union Street at King Street, just steps from the Potomac River, and police officers were towing and moving cars from the area.

No major issues were reported in the District, but D.C. police said that Beach Drive in Northwest continued to be a problem. At 5:15 p.m., police closed West Beach Drive near the Maryland line because of unsafe road conditions.

Officials also said that Hains Point in Southwest, where the Potomac and Anacostia rivers meet, was shut down because of flooding. So was Canal Road from Foxhall to Reservoir roads because of downed power lines.

Earlier Wednesday, District crews removed a tree that fell across Military Road in Northwest, temporarily closing the road from 16th Street to Oregon Avenue, police said.

Urging continued caution on the roads, Piringer said that motorists often don’t realize that even six inches of water is enough to stall a car.

From there, if a driver can’t get started again, the car can become stuck as waters rise.

“It only takes a couple of minutes to have an issue,” Piringer said.

Loudoun Fire and Rescue personnel were called to Tail Race Road near Route 50 in Aldie after a propane truck became stuck in high water just before noon, officials said.

The man driving the truck was able to climb onto the roof of the vehicle, and the fire and rescue department’s swift-water team rescued him by boat, according to Laura Rinehart, a department spokeswoman.

The man was not injured, Rinehart said.

As of 7 p.m., Reagan National Airport had gotten 3.98 inches of rain during the storm, including 2.65 inches Wednesday. Dulles International Airport reported 4.94 inches for the storm, including 3.71 inches for Wednesday.

The rainfall caused sewer overflows at two Washington Suburban Sanitary Commission facilities in Prince George’s. The overflows continued Wednesday night, but officials noted that the agency’s drinking-water system is separate from the wastewater system and is not affected by the overflows.

Caitlin Gibson, Peter Hermann, Dan Morse, Clarence Williams and Julie Zauzmer contributed to this report.

(Photos: Deadly tornadoes rip through central and southern U.S.)

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