A snowman on a traffic median in Nashville, Tenn., on Friday. (Andrew Nelles/Tennessean via AP)

Authorities along the East Coast declared states of emergency in the face of a potentially historic winter storm, urging drivers to stay home and hunker down as a string of dire forecasts and blizzard warnings reverberated throughout the Northeast and beyond. Thousands of flights were canceled as the snowfall approached, with forecasts calling for freezing rain, pounding snowfall and gusting winds.

Capital Weather Gang's Jason Samenow gives the latest forecast and snow accumulation predictions for the potentially historic blizzard hitting the Washington area and the mid-Atlantic. (Ashleigh Joplin,Jason Samenow/The Washington Post)

More than 7,000 flights set for Friday and Saturday had been canceled by Friday night, according to FlightAware.com, which tracks air travel conditions. Airlines began scrapping all flights through major Northeast hubs, with airports in and around Washington, Baltimore, Charlotte and Philadelphia announcing plans to halt flights entirely. Travelers were told they could rebook flights without change fees, while Amtrak said it would reduce service and cancel some trains due to the storm.

The worst of the storm is expected in Washington, where the region’s subway system and buses will stop running over the weekend. From Arkansas to Pennsylvania, officials responded to the storm by closing government offices in some states and declaring emergencies in others.

[A blizzard bears down on D.C.: The final forecast before the storm]

Pennsylvania was placed under a state of emergency for its first snowstorm of 2016. Officials called on residents to stay home, and Gov. Tom Wolf (D) said in a statement he wanted “Pennsylvanians to stay calm, but be prepared.”

The state Department of Transportation said it had about 2,200 trucks, plows and snow spreaders ready to deploy, along with more than 733,000 tons of salt. Trucks had been dispatched in Philadelphia on Wednesday to brine major arteries, bridge decks and elevated streets. Even so, people were asked to stay off the roads, as Leslie Richards, the state transportation secretary, told residents to postpone nonessential travel.

Philadelphia officials announced a snow emergency in the city beginning at 9 p.m. Friday. The Southeastern Pennsylvania Transportation Authority, which operates trains and buses around Philadelphia, said it was halting service on all but two lines beginning Saturday at 4 a.m.

Concerns about the storm reverberated down the Eastern Seaboard and stretched into Southern states. In Tennessee, where poor weather was blamed for a fatal crash earlier this week, all state offices were closed Friday due to severe weather.

The Tennessee Highway Patrol said Friday afternoon that multiple crashes had snarled Interstate 65 in Nashville, closing that major roadway. The patrol’s Nashville district said they had responded to more than 60 crashes between midnight and noon, while the Nashville police warned that Interstates 40 and 24 in the city were impassable. Police there said they dealt with 200 reports of accidents since Friday morning.

State offices throughout Kentucky were closed Friday, while Arkansas Gov. Asa Hutchinson (R) shuttered the state’s offices around the Little Rock area.

Georgia Gov. Nathan Deal (R) declared a state of emergency for 21 counties through Sunday at midnight. Officials also said they were keeping an eye on another 24 counties under a winter storm advisory, a stretch of the state that includes  the Atlanta region. State offices were closing at noon Friday, Deal said, and he urged city governments and local businesses to act similarly.

[Eastern Seaboard braces for potentially historic winter storm]

North Carolina Gov. Pat McCrory said Friday that wintry weather in the state was already responsible for at least five deaths. He declared a state of emergency Thursday as authorities readied for snow and ice expected to arrive through Saturday.

“Given the snow and ice accumulations that are predicted, combined with gusty winds and already saturated grounds, this storm has serious potential,” McCrory said in a statement.

[Look at the snow falling in webcams across the U.S.]

Two people were killed late Wednesday in incidents related to the snowfall and wintry conditions that arrived that day, according to McRory’s office. A woman in Forsyth County died after crashing her car on a road coated with sleet and snow, while a woman in Stokes County drove into a creek after losing control on a snow-covered road, his office said.

McRory told MSNBC on Friday that the death toll had risen to five, saying that two people had died on the state’s roads that day.

He also said that authorities believe the NFL playoff game scheduled for Charlotte on Sunday should still be able to take place. The Carolina Panthers are set to host the Arizona Cardinals in the NFC championship game on Sunday evening.

McRory told the network that many fans who would travel long-distance to Bank of America Stadium likely won’t be able to make it, because of the ice on the roads along with widespread air travel delays and flight cancellations.

“We’re going to ask people to be careful, but we’re hoping by Sunday this thing will clear out,” he said.

Be careful not to catch too many snowflakes on your tongue. Scientists found that snow in urban areas soaks up air pollutants, such as toxic particles in gasoline exhaust. (Jenny Starrs/The Washington Post)

New York’s statewide emergency operations center will activate Friday night, according to Gov. Andrew Cuomo (D). The snow is set to arrive almost exactly a year after New York City’s subway system was shut down due to a looming storm that wound up largely bypassing the city.

This time around, Cuomo suggested that a subway shutdown would not take place, saying that about 1,000 track workers and another 800 station workers, along with heating equipment, would be sent out to keep trains moving and stations clear of snow.

New York Mayor Bill de Blasio (D) also said it did not appear that a subway shutdown would be needed for this storm and urged people to use mass transit if they need to travel.

“We’re bracing for the first big storm of the winter,” de Blasio said during a Thursday briefing with reporters, according to a transcript provided by his office. He added: “We’ve all been lulled asleep a bit by how a warm a winter it’s been. It’s astounding to me that we’re almost to February 1st before we had our first real snowstorm.”

[How to prepare for a big blizzard]

De Blasio on Friday issued a winter weather emergency declaration on Saturday from 8 a.m. to midnight. He sought to reassure residents that the city was prepared for a major storm, saying that thousands of sanitation workers would be deployed and that more than 1,700 vehicles with plows were ready to hit the streets.

The Metropolitan Transportation Authority plans to send out three dozen vehicles to plow and salt bus stops, while the trains on the Long Island Rail Road and Metro-North could switch to limited schedules or halt service entirely, depending on the snow and winds that arrive.

Delaware Gov. Jack Markell (D) declared a state of emergency beginning Friday afternoon and urged people to “take the necessary precautions to protect themselves and their loved ones.”

Birds flock to a feeder as snow falls Friday in Nashville, Tenn. (Mark Humphrey/AP)

In New Jersey, residents were warned to be ready for power outages, poor travel conditions and coastal flooding. Emergency officials warned that heavy snowfall “can immobilize a region and strand commuters, close airports, stop the flow of supplies and disrupt emergency and medical services.

Public Service Electric and Gas Company, the state’s biggest electric and gas utility, said it was preparing for the possibility of downed wires and power outages. It said extra personnel were being dispatched with spare poles and other equipment.

Gov. Chris Christie, who is in New Hampshire campaigning for the Republican nomination for president, had initially said he was not planning to return to the state for the storm. His office said he had a briefing with his cabinet Thursday night to discuss storm preparations and would determine any other steps.

On Friday afternoon, Christie changed course and his presidential campaign announced that he was canceling events in New Hampshire on Friday night and Saturday to head back. Christie tweeted that he was returning to New Jersey on Friday because he wants “to make sure the people of my state feel safe and secure.”

Related:

Amtrak expects service reductions this weekend

How to winter-proof your home

Milk and bread may not be the best survival foods

This post has been updated.