A ferocious storm — a menacing atmospheric concoction of fierce winds, heavy rain and stabs of lightning — swept across the Washington region Monday evening, flooding roads, knocking down trees, and cutting power to tens of thousands of homes and businesses.

At least one person was seriously injured when lightning caused a house fire in Frederick County, Md., authorities said.

At Dulles International Airport, warnings Monday caused hundreds of people to cram themselves into a tunnel out of concern that high winds could smash the terminal’s glass walls. Winds broke a window in an apartment in the Dunn Loring area of Fairfax County, but no injury was reported.

Early Tuesday, there were still some trees down on roads, but no major traffic incidents. Some people were still without power.

About 5,300 customers of Dominion Energy were still without power at dawn Tuesday in Northern Virginia. Of those, more than 2,600 were in the Spotsylvania area and 1,600 were in Fairfax, and another 1,000 in Fauquier counties.

In Maryland, Pepco said about 120 of its customers, mostly in the Bloomingdale area of the District and Silver Spring in Montgomery County, were still without power.

Atmospheric spectacle was presented to Washington residents Monday evening as a line of fierce storms chewed their way across the area. (Photo by Jeremy Kirkpatrick)

Both companies said they had crews working to restore power.

The wave of angry weather roared in before the Monday evening commute.

Trees toppled. They fell onto roads, blocking traffic, and onto at least two cars, both in Northern Virginia. Waters rose and disabled automobiles.

In Northeast Washington, Walter Deleon said “a tree fell onto an ambulance” that had brought emergency personnel to tend to a neighbor. No injuries were reported.

From the safety of their homes, many Washington-area residents marveled at the atmospheric drama of the onrushing clouds that turned skies suddenly dark, but in places gave the skies a weirdly greenish tinge.

Hundreds of people cram a tunnel at Dulles International Airport after being warned away from windows, as severe storm swept through the Washington area. (Photo by Arthur Brooks)

“Rarely have I seen a sky look blue-green,” read a social-media posting.

“A merry apocalypse to YOU,” read someone else’s posting, accompanied by a photo of black clouds that were eerily bounded by a strip of far-off brightness in the skies over the Glover Park neighborhood of Northwest Washington.

At Dulles International Airport, 1.68 inches of rain fell between 6 p.m. and 7 p.m. At Reagan National Airport, the figure was 1.37 inches.

Its pelting intensity curbed visibility and soaked those area residents who somehow missed the forecasts that had circulated through the day.

One man posted a selfie that showed him wearing a shirt covered with dark blotches left by raindrops. “I beat the storm,” he wrote. “Mostly.”

Gina Eosco sent a text message to her aunt, who lives in the Dunn Loring area, telling her to avoid windows. Her aunt, she said, got it in time to avoid injury when the window blew in.

One of the many who traveled the area’s inundated roads was a reporter in President Trump’s motorcade, which returned to the White House from Bethesda.

“Skies were scarily dark, and wind gusts knocked our top- heavy van around a bit,” reporter Steven Portnoy wrote.

After the rain set in, he said, the vehicles “pushed through heavy standing water” on the George Washington Memorial Parkway.

For a time at least, water seemed to be everywhere.

In North Arlington, according to a report made to the National Weather Service, an area flooded near 22nd and Harrison streets. Water rose above the curb, and trash cans went floating down the street like boats in a current.

Trees fell, such as the one that blocked southbound lanes of Route 15 near Route 29 in the Gainesville area of Prince William County, and the one that pierced an automobile windshield on Route 7 in the Vienna area of Fairfax County.

For many, the flashes of lightning served as spectacle.

But they also caused fires. Besides the one in Frederick County, lightning was blamed for a fire on Holly Avenue in the Takoma Park area, according to the Montgomery County Fire Department.

The wind and rain that lashed so much of the region came from a front that stretched well to the north and south of Washington and it rolled implacably southeastward.

In Northern Virginia, almost 50,000 homes and businesses were without power at one point. Other parts of the Virginia also felt the effects of the day’s storminess. Dominion reported 50,000 outages in what it described as the metropolitan Richmond and tri-cities area.

Dana Hedgpeth contributed to this report.