A customer shops in the dark at Ayers Variety & Hardware in Arlington's Westover Village. The family-owned business suffered significant damage from Monday's flash flood. Power was out because of flooding in the basement. (Matt McClain/The Washington Post)

Business owners and residents spent Tuesday assessing damage from a record deluge that stranded motorists, closed the Beltway and even seeped into the White House the day before.

“It was biblical,” Kristy Peterkin, owner of Ayers Variety & Hardware in Arlington, said Tuesday as employees mopped dirt and traces of water off the floor. On Monday, as rain poured down and she waded through waist-deep water in the store’s basement, she wondered whether the flood might wash away the business. By her reckoning, at least $100,000 in inventory was lost.

“We’ve never seen anything like it,” Peterkin, 53, said. “Yesterday was different.”

The rainstorm that drenched the region Monday set a record. In one hour’s time, a month’s worth of rain — 3.3 inches as measured at Reagan National Airport — cascaded across the city. Cars floated off in some places, and leaky Metro stations resembled carwashes. Flash-flood emergency alerts began flashing on phones.

Nearly 5,000 Pepco customers in Maryland lost power during the height of Monday’s storm, mostly because of power lines downed by high winds. All but 125 customers were back on the grid as of Tuesday, most of them before noon, spokeswoman Christina Harper said. Only a small number of people in the Potomac area were still without power by Tuesday afternoon, but that was because emergency officials asked for the power to remain off because of significant flooding.

In Northern Virginia, about 7,000 people had their power knocked out because of the storm, and all were returned to service by the end of the day, Dominion Energy spokesman Jeremy Slayton said.

A day later, things returned to normal except for a few isolated spots, with officials saying most of the mayhem had been short-lived.

But for some, the work was just beginning.

Ayers Variety & Hardware was open, drawing enough power from a generator to make the cash register work. An employee escorted customers through the dimly lit store to help them find what they needed.

Anthony Wessel, left, stands next to Zach Burdette, right, as he puts on a mask to work at Ayers Variety & Hardware. (Matt McClain/The Washington Post)

“You’re the only people who are working,” one woman said as she entered the store. Another who stopped by gave Peterkin a hug. “I’m here to check on my neighbors,” the woman said.

Peterkin showed her the damage done to the basement, and the woman later offered to bring lunch to the store.

Kristy Peterkin, left, and Grace Shea inspect damage in the store's basement. (Matt McClain/The Washington Post)

In Montgomery County, officials were making arrangements for permanent repairs to a giant sinkhole that opened on Belfast Road in the Woodrock neighborhood of Potomac.

Two other major roads — Fenway and Wissioming — remain closed, said Earl Stoddard, director of the county’s Office of Emergency Management and Homeland Security.

“For the most part things have stabilized,” Stoddard said Tuesday. He said workers late Monday temporarily filled the Belfast Road sinkhole with gravel and covered it with a metal plate that allows traffic to travel over it. But permanent repairs will require closing the entire road to traffic for approximately 48 hours, beginning Thursday at 10 a.m., he said. A shuttle service will run 24 hours a day to help people affected by the closure.

In Arlington, 20th Street North and 18th Street remain closed as officials work to make repairs there. They are expected to be fixed by end of the week.

Restoration is going to take a lot longer at ballfields in Virginia. Hundreds of thousands of dollars had been effectively washed away at McLean Little League, which had just invested in major improvements at the complex. In a matter of minutes, its baseball diamonds and buildings became submerged under several feet of water.

“It looked like a lake,” said Tim Steffan, a board member for the organization in charge of fields and facilities. “We’ve never seen flooding like this.”

Pimmit Run Stream overflowed, flattening dugouts, knocking over outfield fences and washing away clay infields, he said. The lower level of an administration building was also flooded. Steffan said the league does not have an official estimate for the damage yet, but he guessed repairs might run to more than $100,000 from the downpour.

Steffan said league officials think they will be offline at least a month, and they are contemplating canceling the fall season and relaunching next spring.

“It peeled my fence like a sardine can,” said Dan Callison, a resident of Annandale who said he had never seen such a powerful storm in his 35 years living there. Within half an hour, a creek that feeds Lake Accotink and runs behind his home became a gushing torrent powerful enough to move whole trees and rip apart his picket fence.

“It all came within 30 minutes,” Callison said. “It was insane.”

Some Arlington residents faulted the county for failing to carry out repairs to storm drains that might have lessened the storm’s impact, despite years of warnings.

Alexandra Lettow said this was the seventh time her home has been flooded since she and her husband purchased the property in 2001. There have been talks with county officials about improving drains that were installed when the neighborhood was built in the 1930s, but no action, she said.

“They know the storm drains are inadequate to handle this type of water event and they’ve been looking into doing something about it, but they pulled all the money out of the last Arlington fiscal budget,” said Lettow, 41. “But in the meantime, we’re flooding — all the time.”

Arlington County officials acknowledged that they have been working with the Waverly Hills neighborhood for several years about its concerns over the feet drains.

Jessica Baxter, communications manager for Arlington’s Department of Environmental Services, said it was an “extremely challenging project” to add storm sewer capacity to the location, but that it is on the county’s capital improvement priority list. It has not, however, been scheduled, Baxter said.

Charlie Lettow, 13, and his mother, Alexandra Lettow, carry a bookcase to the curb as other items, including a laptop, sit outside their home in the Waverly Hills neighborhood in Arlington, Va. The family suffered significant damage from Monday's flash flood. (Matt McClain/The Washington Post)

Justin Jouvenal and Patricia Sullivan contributed to this report.