In Riverdale, the roof of an apartment house was reportedly ripped off.

Trees littered fields, streets and roads in many parts of the area, and some toppled onto houses.

The Chesapeake Bay Bridge, where traffic can be vulnerable to wind, was reported closed. Saturday morning, Amtrak suspended its service from Washington to Philadelphia at least until mid-morning, the Associated Press reported.

Residents of the Mount Vernon area of Fairfax County said the number of falling trees and broken branches littering their neighborhood suggested the sudden and powerful gusts of a powerful downdraft, possibly a microburst.

Metro service was severely affected. Trains were returned to their starting points. At least one tree was reported down on Orange Line tracks.

No power was available between Grosvenor and Shady Grove on the Red Line.

The transit agency said it was trying to fill gaps and come to the aid of stranded riders by creating a bus shuttle, but the heavy weather was delaying the buses.

Whipped by the wind, rain fell sideways in Georgetown. Trees fell onto cars on downtown streets and branches skittered across 12th Street NW.

An opera was halted in the middle of Act II at Wolf Trap. Witnesses said the skies seemed to suggest the onset of a hurricane.

The fury of the storm seemed to be at least in part a product of the record-setting heat of the afternoon. It was the hottest June day on record in the District.

Friday afternoon, on the National Airport tarmac, three men stood in the midst of a swelter that may have been as high as 130 degrees.

Dennis Frederick, Nathan Laryea and Tito Williams stood, arms folded, in sweat-soaked T-shirts and bright orange vests, as they contemplated what awaited them in the cargo hold of the AirTran flight.

They figured 145 degrees, at least? Maybe 120 bags each? About 30 or 40 pounds per bag? Everything off and the new load packed after about 30 minutes in the hold?

It was hot Friday. Everywhere, people chattered about it, notably complete strangers who tend to break the normal silence in elevators and grocery lines whenever the weather — hot, cold, snowy or rainy — gives them something in common to discuss.

Predictable things happened Friday: Swimming pools were busy, people ate more ice cream and those who could do so fled town early for the beaches. The laundry list of heat warnings was trundled out for amnesiacs and visitors who have never known Washington on the eve of July.

The people whose jobs allow them no escape — hot dog vendors, construction workers, bike messengers, meter maids, baggage handlers — sweated.

Some folks sought satisfaction or acclaim by exercising outdoors during the worst of it and sweated along with them. How hot was it?

Records were set across the region as the heat wave that had bedeviled the Midwest reached full blossom here.

The thermometer hit 104 degrees at National and hung there most of the afternoon. Dulles International Airport broke 100 degrees. All-time records also fell all over the South— 109 degrees in Nashville; 108 in Columbia, S.C.; 105 in Raleigh, N.C.; and 104 in Charlotte.

Just as it had been in the Midwest, the heat was blamed for several deaths, including three in Virginia.

“You need to drink a lot of water and stay in the shade,” said Williams, who acknowledged that shade is in short supply on an airport taxiway. At 35, he’s worked for eight years with Flight Service, the contractor that supplies baggage handlers for AirTran and several other airlines.

Frederick figured they each muscle about 1,000 bags a day.

“This humidity is unhealthy,” added Laryea, who is spending his first summer on the crew. “We’ve had a couple of hot ones, but this takes the cake.”

In McPherson Square, members of the Occupy D.C. movement returned to reclaim the ground where they camped out through the winter until departing two weeks ago.

But Friday’s fiery temperatures ruined some of their planned protests, and they headed instead for air-conditioned museums and cafes nearby.

Annie Gowen, Lena Sun, Mihir Zaveri and Susan Svrluga contributed to this report.