This came as Maryland reported three heat-related deaths, and a District woman was said to be recovering from a broken back after a tree fell on her Friday and left her partly paralyzed.
In the District, Mayor Vincent C. Gray requested in a letter that President Obama declare a disaster so the city can qualify for federal funding to cover damage from Friday’s storm.
Utility crews, meanwhile, struggled to repair damage inflicted by the storm that blew down trees, left more than 1 million people in the dark and claimed at least 17 lives.
The weather service noted that although the downpour was violent, May and June make up the peak thunderstorm season in the mid-Atlantic, and a similarly explosive tempest struck the area in 2008.
Hundreds of thousands of people were still without power Monday night, and others who at first had electricity in the aftermath of the storm lost it Sunday and Monday.
Sections of Northwest Washington and Prince George’s County that had power after the storm lost it Sunday, and parts of the National Harbor complex temporarily lost electricity Monday.
That failure was caused by a substation malfunction that was later repaired, Pepco spokesman Marcus Beal said. He added that the other delayed outages may have been caused by repair work or by tree limbs that fell after Friday.
At 10 p.m. Monday, Pepco said 98,000 of its customers were without power in Montgomery County, 41,000 in Prince George’s County and 34,000 in the District.
Baltimore Gas and Electric reported 17,000 without power in Prince George’s and 1,500 in Montgomery. And Dominion said 108,000 of its customers in Northern Virginia were without electricity.
Some people in Washington received unusual relief.
Responding to requests for help from two residential complexes, Metro and the city deployed two “cooling buses” — one to Deanwood, the other to Anacostia — to provide a place to cool off.
“We’re just so happy to have someone concerned,” Juanita Hitchens, 77, of Anacostia said Monday. “It was just a blessing.”
One bus was parked near a nursing home on Nannie Helen Burroughs Avenue in Deanwood, and the other in front of Skyland Apartments, a complex on 24th Street SE.
“Metro didn’t have to do this,” said James Jackson, a Skyland resident.
In Maryland, health officials reported Monday the first three deaths related to the heat wave, one in Montgomery County, one in Wicomico County and one in Baltimore.
The officials declined to provide specifics except to say that the Montgomery County death was a man and that the two others were men age 65 or older.
Virginia has reported six recent heat-related deaths — two in Northern Virginia, two in the central part of the state and two in the western section.
In the District, Carolina Alcalde, 38, of Adams Morgan, was in critical condition at George Washington University Hospital after a tree fell on her Friday as she rode her motorcycle on 15th Street NW, said a friend, Victoria Page Fulkerson.
Fulkerson said Alcalde, a member of a local motorcycle association, was headed home from Virginia, riding north on 15th Street.
“The impact . . . severed her spine . . . so she, as a result, has been paralyzed from about the midsection down,” Fulkerson said. Alcalde also has a bruised lung, fractured ribs and a broken shoulder blade.
“She has a long journey’s recovery, but she has a huge network of friends that are here rooting for her,” Fulkerson said. “She’s an incredible person.”
Also in the wake of the storm, many people remained without phone, cable and Internet service Monday. School programs were closed, and the District announced that its schools would be closed Tuesday as well.
Across the area, residents blundered in the dark with flashlights, slept in basements to stay cool, and emptied refrigerators of spoiling food. Some got relief by returning to work in air-conditioned offices.
Roads remained blocked by downed trees, and traffic signals were dark. The Virginia Department of Transportation lifted the HOV restrictions on Interstate 66 for traffic inside the Beltway during Tuesday’s morning and evening commutes.
HOV restrictions will remain in place for Interstate 66 traffic outside the Beltway, as well as for Interstate 395 and Interstate 95.
Meanwhile, the National Park Service said all of its Fourth of July programs on the Mall are scheduled to go forward.
Spokeswoman Carol Bradley Johnson said that 75 percent of the storm damage to tents and fencing that had been erected for the festivities had been repaired. “Everything that was planned is still planned,” she said.
But Montgomery County canceled Fourth of July fireworks shows in Kensington, Rockville, Germantown and Gaithersburg. County Executive Isiah Leggett (D) said police and fire officials required for the fireworks are needed for recovery efforts.
In Virginia, Jack Brown, director of Arlington County’s Office of Emergency Management, wondered whether that county’s Independence Day events should be canceled.
“I’m questioning having a special event during an emergency,” he said Monday, after a weekend of extreme heat, power outages and the failure of the emergency 911 call system.
“Our power supply is not up and running at full strength, and our emergency communications are not where I’d like,” he said. “I’m really, really concerned about the vulnerability of our community, especially Arlington, but really the whole national capital region.”
Fairfax County spokeswoman Merni Fitzgerald said: “We’re very aware of the week that it is, and we’ll be appropriately staffed. The Fourth isn’t just planned by government, it’s planned by communities, so I don’t see how we could cancel it.”
In Washington, public works officials stationed special trucks at six schools to collect refrigerated food that had gone bad. Officials said the trucks would be available from 3 p.m. to 7 p.m. Monday and Tuesday.
The schools are LaSalle-Backus Elementary, 501 Riggs Rd. NE; McKinley Tech, 151 T St. NE; Key Elementary, 5001 Dana Pl. NW; Wilson High School, 3950 Chesapeake St. NW; Ferebee-Hope Elementary, 3999 Eighth St. SE; and Garfield Elementary, 2435 Alabama Ave. SE.
Although many people were using libraries and cooling centers to beat the heat, some health-care clinics were trying to keep their medicines cold.
The sudden loss of power Friday night meant that many pediatric offices were worried about keeping their many vaccines refrigerated.
About 90 percent of all vaccines need to be stored at temperatures between 36 and 46 degrees, officials said. The chicken pox vaccine needs to be stored in a freezer.
One large Northern Virginia pediatric practice lost power at its Alexandria office on Beauregard Street. Unable to reach personnel at two other offices, the Alexandria staff contacted Inova Alexandria Hospital for help.
By early Saturday, office manager Nicky Lundy and the on-duty physician, Jon Farber, were able to get permission to store hundreds of vials of vaccines, worth more than $100,000, in a hospital pharmacy refrigerator. The Alexandria location still had no power on Monday.
Hospital spokesman Tony Raker said there was no hesitation in granting the request because “patient care comes first.”
Lena Sun, Victor Zapana, Mark Berman, Amy Joyce and Keith L. Alexander contributed to this report.