Most major roadways and many neighborhood streets were passable, although officials cautioned that many on-ramps, acceleration lanes and shoulders were still full of hard-packed snow.
With tens of thousands of people still without power throughout the region, Maryland Gov. Martin O'Malley said Thursday afternoon that "reliability standards" expected of utility companies would be reviewed by the state legislature.
Pepco, which serves the District and much of the Maryland suburbs, said the majority of customers should have power restored by 11 p.m. Friday. The utility was reporting 147,505 customers still without power as of 5 p.m. Thursday.
In Northern Virginia, where 50,777 customers remained without power as of 5 p.m. Thursday, Dominion Virginia Power said it was borrowing work crews from other areas to get the lights back on. The utility said it hoped to have power restored to 90 percent of customers by Friday night.
"We have about 2,000 workers engaged in our restoration effort, including crews from Eastern and Central Virginia and North Carolina assisting in Northern Virginia," said Rodney Blevins, vice president of electric distribution operations.
The outages hit poor and powerful alike. District Mayor Vincent C. Gray (D) returned home after crisscrossing the city and discovered his home had no power, a spokeswoman said. Pepco said 19,683 D.C. customers remained without power Thursday afternoon.
Montgomery County was particularly hard hit. It had by far the largest number of powerless homes, about 105,596 at 5 p.m. Despite a full deployment of Pepco crews, that number had increased by more than 200 since noon, the result of heavy, wet snow continuing to topple trees.
In addition to homes, the outages affected some 200 traffic lights, officials said.
Montgomery County has more power lines above-ground than many of its neighbors, said Pepco spokesman Bob Hainey. In addition, a substation in Kensington suffered damage and had to be shut down, he said.
The county is directing snow-clearing crews to neighborhoods with widespread outages so families without heat can emerge and seek help. A shelter opened at Richard Montgomery High School in Rockville, officials said.
Montgomery officials declared a road emergency about midnight. That allowed hundreds of abandoned vehicles, - which both fed the epic gridlock Wednesday night and hampered emergency workers and repair crews - to be towed.
Prince George's opened a warming shelter for residents without power at the Sports & Learning Complex in Landover.
The icy roads that led to paralysis on the highways and darkened neighborhoods caused many local governments to close Thursday, including the District's. Even the ice rinks in Montgomery County didn't open, because the roads for skaters to drive there were so treacherous.
BG&E reported 46,860 without power across Maryland as of 5 p.m. The utility said it hopes to have power restored to most of its customers by Saturday.
The federal government opened, however, granting workers a two-hour delay. Employees also were advised that they could take unscheduled leave or telework from home, according to the Office of Personnel Management.
Different jurisdictions offered different advice. Major arteries in the District are open with rush-hour restrictions on parking in place, but some suburban authorities advised residents to stay home.
"The city is pretty much open for business," John Lisle, spokesman for the District Department of Transportation, said just before sunrise Thursday. "The downtown streets have been plowed. It's not curb to curb yet, but they are clear."
Lisle said plows were at work on every route in residential neighborhoods.
"Most residential streets have a slushy coat and we're treating that with salt because there's not enough to plow," he said.
Lisle urged residents to shovel their sidewalks.
"In terms of driving, you can get where you need to go," he said. "The problem is going to be on the sidewalks. The last thing we want is people getting hit because they have to walk in the street."
The Virginia Department of Transportation encouraged people to stay home until the roads can be cleared of snow, abandoned cars, trees and power lines.
VDOT has had plows and salt trucks working since before the first snow flake fell on Wednesday, but it warned that many roads were still snow-covered, barely passable and too slippery to drive on.
The plowing has been made more difficult by dozens of vehicles abandoned on roadways at the height of the storm Wednesday night.
Major highways, such as Interstate 66 westbound, became a perilous maze with cars, trucks and SUVs abandoned on the shoulder, some stuck out into traffic lanes just enough to pose a danger. Montgomery County declared a snow emergency and told motorists to get their vehicles off snow emergency routes or they would be towed.
Airports seemed to roused from a deep sleep, looking like the morning after a giant sleepover as hundreds of travelers spent the night at Dulles International and Reagan National airports because of canceled flights, according to Metropolitan Washington Airports Authority spokesman Rob Yingling. The airports distributed blankets, and restaurants stayed open late.
There were widespread flight cancellations Thursday morning as airlines repositioned planes and crew to meet their schedules, but normal operations gradually resumed throughout the day.
At least one person is known to have died because of the storm. Oswaldo Hernandez-Cruz, 41, of Hyattsville, was found unconscious on Military Road after a tree fell on the car he was driving, police said. Three other passengers in the car were rescued by emergency workers.
The dissection of what went wrong started before the snow stopped falling shortly before midnight.
The commute home Wednesday night that took hours instead of minutes, caused scores of collisions and left the region scattered with abandoned cars was a conspiracy of weather and timing that had hellish results.
The storm took no one by surprise, and even after days of pondering its shape and potential impact, by the time it arrived weather forecasters were accurately foreshadowing what would happen.
Road crews in both states and the District prepared for snow as they normally do, pretreating streets with salt and, in some cases, a calcium chloride mix, intended to melt the initial snow or ice.
But on Wednesday the worst of the storm was preceded by a heavy rain that washed away most of those chemical pre-treatments. Then, just as the mix of sleet and freezing rain started - and before crews could intervene again- the rush hour home began early.
Salt trucks that might have mitigated the effect of the fresh layer of ice were trapped in the same traffic jams that drivers were. And very quickly those trucks were stuck behind cars that were spinning their wheels on hills and buses with modern technology that caused them to shut down when they lose traction.
"When the storm hits right at rush hour this will always be a problem," said John B. Townsend III, a spokesman for AAA.
Townsend was stuck in traffic for more than two hours last night as he made his way from downtown Washington out New York Avenue en route to his home in Prince George's County.
"Everybody was taking it in stride, but if this was a test to prepare us for what's likely to come in February, we got an F," he said.
Gray promised to "do the best we can" in the District. Prince George's County warned that it could be 12 hours after the last flake before plows liberated neighborhood streets. And Northern Virginia and Montgomery County were counting on revamped game plans designed to temper the public fury unleashed a year ago.
"One of the lessons learned from last year was to manage expectations," Lisle said.
After a drizzly, dreary start Wednesday, the storm struck with fury beginning at mid-afternoon, causing whiteout conditions across the region and casting a wintry glaze on roads and sidewalks that sent cars spinning and people tumbling.
The criticism that turns officials timid resurfaced quickly Wednesday after the federal workforce was sent home two hours early, creating massive traffic backups on icy streets.
Even the president, returning from factory tours in Wisconsin, got a rare taste of traffic. His motorcade, which normally sails unfettered from Andrews Air Force Base to the White House, bobbed and weaved instead, tripling its travel time.
John Berry, head of the Office of Personnel Management, said in an e-mail that he fretted all day before sending federal workers home.
"We allowed two hour early departure ... without a flake in sight," Berry said. "As late as 4 p.m. I was worried, with nothing happening, if the exact opposite was going to occur ... a laughingstock story of overreaction."