Governor Charlie Baker declared a state of emergency at noon Saturday, just as coastal waters again rose during a third consecutive high tide driven by Friday’s nor’easter, which produced extensive flooding, killed one man, and left thousands without power.

Baker had activated the Massachusetts National Guard on Thursday to help local firefighters and police respond to the storm.

A 36-year-old Plympton man died Friday after a large tree fell on the roof of his truck, according to Plymouth District Attorney Timothy J. Cruz. Ryan MacDonald was the sole occupant of the Dodge Ram when the pine crushed the vehicle, Cruz said in a statement.

According to the Massachusetts Emergency Management Agency, 263,705 electricity ­customers in Massachusetts were without power as of 10 p.m. Saturday, following the pounding winds that blew across the state Friday, with the highest concentration of ­outages ­reported on Cape Cod and in Southeastern Massachusetts.

Thirty-two long-term health care facilities were on generator power Saturday afternoon, with 26 of those in Southeastern Mass., according to MEMA.

Utility companies expect full restoration to take several days, in part because continuing high winds made it difficult for crews to use bucket trucks to reach electric cables, according to MEMA.

Kurt Schwartz, director of MEMA, said Baker declared a state of emergency after it became clear overnight that storm damage extended far beyond the state’s coast and that “communities throughout Eastern Massachusetts saw hundreds, if not thousands of trees fall and damage houses and utility poles, leaving massive amounts of debris and impassable roads.’’

Baker’s declaration allows the state to use federal and interstate resources to assist in the recovery effort, the governor’s office said in a statement. Already, the National Guard has deployed 140 emergency responders and 53 high-water rescue vehicles to support rescue efforts.

At Logan International Airport, at least 120 flights were canceled because of the storm, according to Massport spokeswoman Jennifer Mehigan.

Winds declined somewhat Saturday but were likely to remain blustery through Sunday and into the early hours of Monday morning, when light snow is expected in the region, according to the National Weather Service in Taunton.

Wind and waves will diminish significantly by Tuesday, but another nor’easter is possible Wednesday into Thursday, the weather service said.

Boston reached a high tide mark of 13.9 feet just before noon Saturday, according to Bill Simpson, a meteorologist with the weather service, about the same as the previous high tide at midnight Friday. Both were lower than the 14.67 feet reached shortly after 11:15 a.m. Friday morning.

Tides were slightly higher outside the shelter of the harbor, as in Scituate, where the water reached 14.2 feet just before noon, lower than the 14.6 feet it had reached late Friday night, the weather service said. When tides reach 11.5 feet off Scituate, coastal flooding begins, Simpson said.

Christine Ball, who was walking her dog in Scituate on Saturday afternoon, said her Beaver Dam Road home was spared flood damage, though on Saturday her family had to use a generator to warm the house.

“You feel a little pioneerish, and it gets a little old pretty quickly,’’ she said.

Bill Montanari, who bought his home on Jericho Road in Scituate in 1972, said he has seen some weather over the years that was worse, including the Blizzard of ’78, but Friday’s coastal storm still packed a strong punch.

“The wind was unbelievable, and the three tides, and the storm stalling off the coast — when that happens, it’s not good,’’ said Montanari. “I had waves in the harbor like I’ve never seen before.’’

At noontime in Boston, a handful of people gathered at Fan Pier Park in the Seaport District to watch as waves from the harbor crested onto the sidewalk amid whipping winds.

“You’ve got to watch out — seriously!’’ yelled 6-year-old Abra Ordorica, as a wave crept up onto the pavement behind her father, Dan Ordorica, 42.

Jay Kumkum, 13, from Framingham, never saw the water coming as he posed for a photo, jumping forward with a yelp as harbor waters surged over his sneakers.

“Soaked,’’ he said.

It was the wind, though, that caused the most havoc — “so windy your umbrella can break,’’ Abra said.

At a nearby Japanese restaurant, LoLa 42, the wind had smashed chest-high patio dividers into a giant flower pot Friday night as an employee tried to hold them down, according to chef Josh Carter, leaving a pile of broken glass, pottery, and soil.

“I haven’t seen a storm this bad,’’ said Carter, 29, who previously worked at the restaurant’s Nantucket location.

Cities and towns up and down the coast closed roads near the shore and opened shelters and warming centers.

In Quincy, as city crews prepared for high tide Saturday morning, about 50 people remained sheltered in school buildings, Mayor Thomas P. Koch told reporters. No storm-related injuries had been reported among residents, he said.

Koch said city officials were developing cleanup plans to pick up debris cluttering some local roads. The city’s schools will be open Monday, despite some minor storm damage, he said.

“Across the board, this is the most damaging [storm] and I’m very concerned about the infrastructure damage,’’ Koch told reporters.

Late Saturday morning, a group of Quincy residents were offloaded from the back of a National Guard truck to make their way to the city’s high school, which was serving as a shelter.

Karl and Carol Sharicz were planning to spend Saturday night in a Boston hotel after braving Friday evening in their unheated Sea Avenue home, which lost power about noon Friday.

Their home is on high enough ground to avoid flooding, Karl Sharicz said, but they experienced the rest of the storm’s impact.

“No power, high winds, shingles pulling off neighbors’ rooftops, and we’re sitting there watching,’’ he said.

Chris Burrows, a Sea Street resident for three years, said he didn’t evacuate, despite the rising flood waters a few doors down. By noontime Saturday, he wasn’t concerned about the water, he said.

“I just want the power back,’’ he said, “so I can play video games before I go back to work on Monday.’’

Globe correspondents Lucas Phillips and Jacob Geanous contributed to this report. Jeremy C. Fox can be reached at jeremy.fox@globe.com.