More than 4,000 flights have been canceled as the Northeast braces for a winter storm

More than 4,000 flights scheduled for Friday and Saturday have been canceled, as snow begins to pound the Northeast. In some areas, the snow accumulation could reach as high as 2 feet, and the snow and wind could yield blizzard conditions, according to the National Weather Service.

In Boston, which could see more than 18 inches of snow this weekend, at least 92% of flights out of Logan International Airport on Saturday have already been canceled. At LaGuardia Airport in New York, 91% of Saturday's flights have been grounded.

Meanwhile, more than 400 JetBlue flights and more than 440 American Airlines flights across the U.S. scheduled for Saturday have been canceled.

A winter storm warning is in effect Friday from Virginia to Maine, according to the National Weather Service. Snow has already begun to fall in some regions, including the D.C. Metro area and New York City, ahead of the evening commute.

Blizzard warnings have been issued for parts of Maine, Massachusetts and New Jersey, among others. On Friday afternoon, the blizzard warning expanded to cover all of Rhode Island, southern Delaware and parts of Long Island. Coastal areas could see some of the highest accumulations.

On Friday, Boston Mayor Michelle Wu declared a snow emergency. In anticipation of heavy accumulations and high winds, Wu announced a parking ban that will take effect at 9 p.m. on Friday. Under the ban, vehicles parked on major roads and "main arteries" will be towed.

City employees have already begun preparations, and the Public Works Department plans to treat roads before snow begins to fall, Wu said in a statement. The city has 38,000 tons of salt and more than 850 pieces of equipment to use on local streets.

In New York, Gov. Kathy Hochul on Thursday directed state agencies to prepare for the storm. The state's Transportation Department has more than 1,500 large snowplows on hand. The Division of Homeland Security and Emergency Services is prepared to deploy generators and sandbags, among other items.

"We are monitoring forecasts and making emergency response preparations for whatever this storm system throws our way," Hochul said in a news release.

Farther up the coast, the Maine Emergency Management Agency encouraged motorists to stay off the roads. Gov. Janet Mills urged people to "be mindful of road crews and emergency responders."

Powerful winds and blowing snow could create low visibility, making for "hazardous conditions," said Peter Rogers, director of the Maine Emergency Management Agency.

With subfreezing temperatures expected, it's a good idea to keep blankets, extra layers, hats and gloves in the car. And if you get caught in a storm, experts encourage you to stay in the car.

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