First big storm of the year hammers much of Mass.

A pedestrian crossed Kneeland Street in Boston during Saturday’s storm. Matthew J. Lee/Globe staff

The crowds that streamed into Friends’ Marketplace in Orleans Saturday reminded grocer Brian Junkins of an equally busy time — but in a warmer, sunnier month.

“For a few hours this morning, it felt like it was almost Fourth of July week,” Junkins said in a telephone interview. “We’ve basically done three-quarters of a day’s worth of sales in a few hours.”

Junkins and his customers were in the unenviable position of having to prepare for the most treacherous conditions of 2017’s first major storm, which threatened to dump nearly 2 feet of snow on parts of Southeastern Massachusetts, the Cape, and the Islands.

The region was under a blizzard warning Saturday as residents braced for sustained gusts of more than 35 miles per hour and visibility of less than a quarter of a mile, according to Alan Dunham, a meteorologist with the National Weather Service in Taunton.

The weather service said early Sunday that parts of Plymouth County could receive more than 20 inches of snow.

RELATED: Snowfall totals by town

In Boston, the weather service estimated snowfall would stop around midnight.

Governor Charlie Baker warned residents to stay off the roads, clear driveways and sidewalks, and check on neighbors who might need help.

“We do encourage the public to stay off the roads during weather like this if they don’t absolutely, positively have to travel,” Baker said Saturday afternoon during a news conference at the MBTA Operations Control Center in Boston.

In Plymouth, one of the communities expected to bear the brunt of the storm, people rushed to buy groceries at The Market at The Pinehills.

“It’s absolutely insane,” said Leslie Romano, a manager at the independent grocery store. “We have 250 people going through the registers each hour, and we only have four registers.”

Because of the storm, the store decided to close Saturday at 2 p.m., according to a Facebook post.

Massachusetts Department of Transportation crews began pretreating roads on the Cape at 7 a.m., Highway Administrator Thomas J. Tinlin said. The transportation department had more than 3,400 pieces of equipment on the roads across the state by Saturday evening.

Speed limits were reduced to 40 miles per hour on the Massachusetts Turnpike between the New York border and Route 128, and Tinlin urged motorists to give snowplow operators plenty of room to work.

Pedestrians walked through Boston Common in the middle of the storm.Jonathan Wiggs/Globe Staff

On Friday, snowplows in Boston and Bourne were struck by other vehicles, adding to about a dozen crashes in the past three weeks involving cars colliding with plows, Tinlin said.

He warned that drivers might encounter conditions that wiped out visibility, especially in southern Massachusetts.

“It’s really the wind. It’s the whiteout conditions, and it’s the driving conditions,” Tinlin said.

Baker said there had been a series of minor traffic crashes, but no major incidents.

In Connecticut, a crash involving as many as 20 vehicles closed a section of Interstate 91 in Middletown, though no serious injuries were reported.

Boston Mayor Martin J. Walsh did not declare a snow emergency or ban parking on city streets but said in a statement that liquid de-icer and more than 30,000 tons of salt were at the ready. Just before 3 p.m., Walsh announced in a tweet that more than 580 pieces of equipment had been deployed to clear streets, sidewalks, and crosswalks.

Boston property owners are required to clear snow from sidewalks around their homes and businesses within three hours after snow ends or three hours after sunrise if it snows overnight, Walsh’s statement said. If the snow is not cleared, property owners could face fines of $50 to $200.

On Boston Common Saturday afternoon, families were taking advantage of the weather to sled while dogs played in the freshly fallen snow. Some of the youngest sledders looked like marshmallows in their winter gear as they tried to keep up with indefatigable older siblings.

Further south, people were clearing snow by early afternoon.

On Nantucket, Union Street Inn owner Ken Withrow was shoveling by 12:45 p.m.

“It’s coming down pretty hard,” said Withrow, who had closed his business for the season.

The Steamship Authority and Hy-Line Cruises canceled boat trips between Nantucket and Hyannis because of the weather. Boston Logan International Airport remained open, but about 270 flights had been canceled as of Saturday afternoon, a spokeswoman said.

Sagar Bhatt (left) and his fiancée, Megha Parikh, had a snowball fight on Boston Common.Matthew J. Lee/Globe Staff

By 3:30 p.m., Oak Bluffs on Martha’s Vineyard had been blanketed in 8 inches of snow, half of which fell in an hour, according to the Massachusetts Emergency Management Agency.

Helen Cassels, co-owner of the Inn at Cape Cod in Yarmouth Port, said the inn had closed for the weekend because of the snow. She was working on bookkeeping, she said, while her husband painted and decorated rooms.

“You just can’t do much about it,” she said Saturday morning. “You just have to keep warm and safe.”

At the Chatham Squire in Chatham, general manager Richard Sullivan said the restaurant has a generator and he planned to stay open. He said he expected to get business from families who normally stop in during snowstorms.

“We’ve had some pretty bad ones over the last few years,” Sullivan said. “We’re battle-tested a bit down here.”

The Massachusetts Bay Transportation Authority said Saturday afternoon that its subway system was running smoothly as train cars on the Orange, Red, and Blue lines used de-icing equipment and plows.

But, just before 5 p.m., shuttle buses replaced service between Ashmont and Mattapan because of problems with the snow. The Silver Line also had moderate delays due to weather-related issues, according to the MBTA website.

Since 2015, when the T buckled under the weight of a historic winter, Baker said more than $100 million has been spent on track heaters, replacement third rails, and other equipment.

Ninety-seven percent of commuter rail trains were running on time as of Saturday afternoon, said David Scorey, general manager of Keolis Commuter Services. Full commuter rail service was planned for Saturday evening, Sunday, and Monday, he said.

Transit Police Chief Kenneth Green said officers planned to try to get homeless people into shelters but would let them stay inside North and South stations if necessary.

Colder temperatures are expected Sunday and Monday, but no precipitation was in the forecast, Dunham said. Those days will be breezy, with temperatures in the low 20s, but feeling more like high single digits or low teens, Dunham said.

Tuesday is expected to warm up to the low 40s with a chance of scattered showers, Dunham said. Wednesday should be warmer still, reaching the low 50s, also with the possibility of rain.

A food delivery rider bicycled on Charles Street during the storm. Matthew J. Lee/Globe Staff

Plows along Route 53 in Hanover during whiteout conditions in the late afternoon.John Tlumacki/Globe Staff

Snow fell in Copley Square while a dog pranced along Boylston Street in its booties. John Tlumacki/Globe staff