WASHINGTON — A winter storm that could bury parts of the mid-Atlantic region under nearly 3 feet of snow slammed into Washington, D.C., on Friday afternoon, threatening the nation’s capital with record accumulations as it barrels up the populous East Coast.

After emergency officials planned and residents scrambled for days to stock up on supplies, the blizzard started to blanket the Washington area during the early afternoon after six people had died in car crashes as a wintry mix spread across Arkansas, Tennessee and Kentucky.

The storm could dump 2 to 2½ feet of snow on the capital and bring winds of 30 to 50 mph before winding down late Saturday afternoon, according to the National Weather Service.

By then it would have moved over Philadelphia and New York, bringing 12 to 18 inches of snow.

Washington’s western suburbs may get up to 3 feet, forecasters said. In Falls Church, Virginia, about 8 miles west of the capital, a thick curtain of snow was already piling up on the deserted streets on Friday evening, creating a peaceful tableau that may have disguised dangerous conditions to come.

“I want to be very clear with everybody. This is a major storm,” Washington Mayor Muriel Bowser said as the city braced for what could turn out to be one of the worst storms in its history. “This has life-and-death implications and all the residents of the District of Columbia should treat it that way.”

The Weather Channel said more than 85 million people in at least 20 states were covered by a winter weather warning, watch or advisory.

The storm was due to miss northern New England and in Bangor, Maine, which sees 4 feet of snow in a typical winter, police took to social media to advise residents of the mid-Atlantic region on how to prepare for a blizzard.

“Don’t panic. It’s just frozen rain,” the Police Department said on its Facebook page. “DO NOT, I repeat, DO NOT buy all the bread on the shelves. As a lifelong Mainer, I recommend cereal.”

Airlines canceled nearly 6,300 flights for Friday and Saturday, most of them at airports in the New York and Philadelphia areas, according to FlightAware.com.

Bangor International Airport and the Portland International Jetport were reporting multiple cancellations out of major hubs such as Philadelphia and Washington, D.C.

All of Bangor’s American Airlines departures, two to Philadelphia and one to Washington, were canceled Friday, while Portland International Jetport reported numerous cancellations to Philadelphia and the nation’s capital, along with Charlotte, North Carolina.

Both of Bangor’s scheduled departures to New York’s LaGuardia Airport on Saturday have been canceled, along with both departures from LaGuardia to BIA.

Washington’s snowfall could eclipse the “Snowmageddon” storm of 2010 that dropped 17.8 inches, AccuWeather senior meteorologist Alex Sosnowski said. If forecasts prove accurate, the storm could rival the 1922 Knickerbocker storm, which dumped a record 28 inches on the city.

“I think it’s going to be a nightmare, the rates of snow we’re talking about,” said Marisa Kritikson, 27, a nursing student at George Washington University in Washington, after buying a snow shovel to dig out from her basement apartment.

New York Mayor Bill de Blasio asked people to limit travel to “absolute emergencies” as he declared a winter weather emergency for the largest U.S. city.

“There will be whiteout conditions,” he said at a news conference ahead of the storm’s arrival, which is expected after midnight. New York accumulations could reach up to 18 inches, with winds gusting to 50 mph, whipping up blizzard conditions.

Southeastern Pennsylvania, including Philadelphia, was expecting 10 to 18 inches of snow.

The approaching storm led New Jersey Gov. Chris Christie to return to his home state from New Hampshire, where he is vying for the Republican presidential nomination.

Earlier he insisted he would stay on the campaign trail but on Friday afternoon he tweeted: “I want to make sure the people of my state feel safe and secure.”

Residents along New Jersey’s coastline were preparing for potential flooding during high tides on Saturday and Sunday. In the beach community of Ocean City, emergency management officials warned of forecasts calling for the highest flood levels since Superstorm Sandy brought heavy damage in 2012.

High winds and a full moon could combine to create a high tide of nearly 8 feet in Atlantic City, officials said, still shy of the 10 feet that Sandy caused in Ocean City.

In New York City, the National Weather Service issued coastal flood warning for the boroughs of Staten Island, Brooklyn and Queens as the city officials prepared for possible evacuations from low-lying areas.

The New York area’s rebuilding after Sandy puts it in a stronger position to face the approaching storm, New York Gov. Andrew Cuomo said. “We are in a different physical environment,” he said.

The storm arrived in the Washington area, home to about 6 million people, after pushing across Arkansas, Tennessee and Kentucky. It dropped 5 inches of snow in Arkansas and a wintry mess of snow, sleet and freezing rain in parts of Tennessee and Kentucky.

In addition to several inches of snow, the Charlotte, North Carolina, area could get up to a half inch of ice, causing concerns about power outages and dangerous driving conditions, officials said. Other parts of the state could get a foot of snow.

Federal offices in the Washington area closed at noon Friday to allow employees to get home before the snow began piling up. City officials said everyone except emergency workers should stay off the streets.

In anticipation of the blizzard, many residents had scrambled to prepare, picking stores clean of bottled water, food and other supplies.

“I have nine cases of wine, half and half and coffee, firewood and all my devices are charged. All I need now is a wing and a prayer,” said Liz Scherer, 54, who works out of her home in the Washington suburb of Silver Spring, Maryland.

The Washington Metropolitan Area Transit Authority, which includes the second-busiest U.S. subway system, took the rare step of suspending operations from late Friday through Sunday.

The Metropolitan Transportation Authority, which operates New York City subway and commuter rail lines, expected to operate normal service, Cuomo said, as did New Jersey Transit.

The forecast prompted the Virginia National Guard to bring in about 300 troops to deal with emergencies. In New York, 600 National Guard personnel were on standby.

BDN writer Ryan McLaughlin contributed to this report.