BOSTON — A winter storm lashed the Northeast with deep snow and wind gusts near hurricane force Saturday, causing coastal flooding and threatening widespread power outages while forecasters warned conditions would worsen as the day went on.

Parts of 10 states and some major population centers — including Philadelphia, New York and Boston — were pummeled by the storm. By late morning, more than a foot (30 centimeters) of snow had fallen on parts of New Jersey’s shore and eastern Long Island.

Boston, in the nor’easter’s crosshairs, could get as much as 2 feet (61 centimeters) of snow. Isolated pockets nearby could get as much as 3 feet (1 meter), forecasters said. Winds gusted as high as 70 mph (113 kph) on Nantucket Island off Massachusetts and over 60 mph (96 kph) elsewhere in eastern Massachusetts and Rhode Island.

Most flights into and out of the airports serving New York, Boston and Philadelphia were canceled Saturday, according to FlightAware. More than 4,500 flights were canceled across the U.S. Amtrak canceled all of its high-speed Acela trains between Boston and Washington and canceled or limited other service in the region.

Across the region, residents hunkered down and avoided travel at the behest of government leaders, who warned of whiteout conditions. Business closed or opened late.

In suburban Boston, a bundled-up Nicky Brown, 34, stood at the doors of Gordon’s liquor store in Waltham, waiting for it to open. It was supposed to open at 8 a.m., and it was already well past that.

“My boyfriend is out driving a plow, and I had a bunch of cleaning to do at home, and I want a drink while I’m doing it,” she said, as she called the store to find out if it planned to open at all. “It’s a good day to stay inside and clean.”

In the seaside town of Newburyport, north of Boston near the New Hampshire border, officials strongly encouraged residents living along the shore to move to higher ground.

Video posted on social media showed wind and waves battering North Weymouth, south of Boston, flooding streets with a slurry of frigid water. Other video showed a street underwater on Nantucket.

Tens of thousands of homes and businesses lost power in Massachusetts, with failures mounting. No other states reported widespread outages.

The storm had two saving graces: Dry snow less capable of snapping trees and tearing down power lines, and its timing on a weekend, when schools were closed and few people were commuting.

Officials from Virginia to Maine warned people to stay off the roads.

Rhode Island, all of which was under a blizzard warning, banned all nonemergency road travel starting at 8 a.m. Fierce winds blew the snow sideways for hours in Providence.

In West Hartford, Connecticut, a tractor-trailer jacknifed on Interstate 84, closing several lanes. Massachusetts banned heavy trucks from interstate highways.

On New York’s Long Island, East Hampton officials reported near-whiteout conditions, as much as 8 inches (20 centimeters) of snow by midmorning and wind gusts of over 50 mph (80 kph).

“There’s a lot of drifting of snow, so of course we’re urging people not to go out at all, allow the highway crews to do their job,” Town Supervisor Peter Van Scoyoc said. “It’s going to be challenging enough without people getting stuck in the roadway.”

In Philadelphia, where 6 inches (15 centimeters) was reported by early Saturday, few drivers ventured onto streets covered in knee-high drifts.

Some parts of the Jersey Shore had more than 13 inches (33 centimeters) by midday, the National Weather Service reported.

Delaware allowed only essential personnel to drive in two of its three counties.

Many hardy New Englanders took the storm in stride.

“This is nothing,” said Brown, who has lived in Waltham nearly her whole life, except for a brief stint in northern Maine. “I’ve seen way worse up there.”

Dave McGillivray, race director for the Boston Marathon, jokingly invited the public to his suburban Boston home on Saturday for a free snow-shoveling clinic.

“I will provide the driveway and multiple walkways to ensure your training is conducted in the most lifelike situation,” he said.

Parts of 10 states were under blizzard warnings: Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York and New Jersey, along with much of the Delmarva Peninsula in Delaware, Maryland and Virginia. Areas closest to the coast were expected to bear the brunt of the storm.

Virginia, where a blizzard this month stranded hundreds of motorists for hours on Interstate 95, did not hesitate to get resources at the ready. In Maryland, the governor mobilized the National Guard.

Washington and Baltimore were spared the worst of the storm.

The worst of the storm was expected to blow by Sunday morning into Canada, where several provinces were under warnings.