SARNIA, Ont. - A family en route to a beach vacation, truckers hauling loads, commuters and even a British hip-hop star unwittingly joined a 300-strong fraternity of snowbound motorists trapped in vehicles overnight as a fierce storm walloped southwestern Ontario.

With everyone believed to have been rescued from snow-swept Highway 402 by late Tuesday afternoon, all that was left was a final sweep to make sure no one was missed -- and a massive cleanup of snow and abandoned vehicles.

Some 300 people were thought to be stranded when drifting snow and zero visibility forced police to close a 30-kilometre stretch of the highway east of Sarnia on Monday.

Motorists had no option but to hunker down in their vehicles. It was the only shelter available to guard against the bone-chilling night as they awaited help.

That aid came with the daylight, as military helicopters and buses were employed to take 237 people to safety. It was unclear how many others were rescued by farmers and snowmobilers.

"All their checks have revealed that no one has been missed, and they've rescued them," said Ontario Community Safety Minister Jim Bradley, who added officers were double-checking to be "absolutely sure."

"It's still snowing -- the last report I got -- and officers were saying they could not see their hands in front of their faces last night. So we're glad we didn't lose anybody."

One person rescued had an unspecified medical emergency, but was said to be OK. There were no reports of serious injuries or deaths.

The motorists were trapped between Sarnia and County Road 22, and many used the "buddy system," banding together in one vehicle to save fuel, police said.

In all, some 360 vehicles were stuck.

With the storm that buried Sarnia tracking east to London, emergency officials were keeping a close eye on the region to see if a "duplication of this ends up on (Highway) 401," Bradley said.

Middlesex County, bordering London, had declared a state of emergency by late Tuesday afternoon. The weather was so severe that plows were pulled off the roads.

A farmer who lives on London Line, just south of Highway 402, ended up hosting some 30 stranded travellers -- including the British musician Tricky.

John Prins found the artist's tour bus among several dozen vehicles stuck in drifts near his house Tuesday. The band was scheduled to play Tuesday night in Minneapolis, according to its website.

"They were sitting in their tour bus for 30, 35 hours," without any food, the 50-year-old said in a phone interview Tuesday night. "They said they were surviving on Jack Daniels."

Prins had started checking up on stranded motorists Monday morning. He brought a handful of truckers inside for breakfast and when the weather didn't clear up, fetched them again for supper.

"By that time, a lot of their engines weren't running, because of the snow," said Prins, who invited seven truckers to stay overnight.

On Tuesday morning, Prins went out again, this time venturing a few kilometres away, he said.

Prins and his wife knocked on neighbours' doors to borrow food. One of the neighbours, a farmer, used his equipment to dig out the trucks and create a single-lane path on the road, Prins said.

A family with visions of a Mexican beach in their heads found themselves huddled for warmth under thin shawls overnight. The Bhushan family was en route Monday to Detroit for a flight to warmer climes when the fierce storm battered the southwestern reaches of the province.

"We didn't know what to do," said Suhani Bhushan, 19, who spent the night in the car with her parents and sister. "No one wanted to talk because it was so cold."

While waiting for police to find them on London Line, which runs parallel to the highway, the Mississauga, Ont., family would run the car for five minutes every half-hour in an effort to keep warm.

When the rescue team arrived, the four travellers were more than willing to abandon their car and luggage for the warmth of a nearby Tim Hortons.

The coffee shop, just east of Sarnia and south of the highway, provided safe haven for dozens of travellers. Some people who arrived at the shop early Monday were still there as of early Tuesday.

"It's been heartening to see the response of local folks as well -- farmers and others -- who have assisted," said Bradley, the community safety minister.

Emergency Management Ontario continues to co-ordinate the rescue and snow-clearing work, and 100 provincial police officers are on the scene.

The military is also sending in three "heavy-tracked vehicles" from CFB Trenton, which were expected to arrive Tuesday night. The large vehicles are used to carry troops and can move more easily through snow than ordinary vehicles.

Those trapped were dealing with temperatures around -15 C but it would have felt like -25 C with the windchill, said Environment Canada meteorologist Geoff Coulson. Occasional 70 km/hr wind gusts blew around 30 to 40 centimetres of snow, causing significant whiteout conditions.

London, paralyzed last week by more than a metre of snow, could pick up 40 centimetres of fresh snow before the early hours of Thursday.

Ontario wasn't the only province being pounded by extreme weather.

Powerful winds and rain battered New Brunswick, partially tearing off the roof of a retirement home, knocking out power for tens of thousands of people and causing the St. John River to swell near its banks.

In Nova Scotia, high winds downed trees and power lines.

Emergency Management Ontario had issued a Red Alert late Monday for the Sarnia area because of the snow and lack of visibility, meaning the area could get assistance from Ottawa. The Red Alert ended around 9:30 a.m. Tuesday.

Warming centres were opened in the communities of Wyoming, Watford, Forest and Warwick.

Peter Andersen, a truck driver from Oakville, Ont., was trapped in the storm just east of Sarnia on Monday morning. That evening, the 42-year-old reached into the truck's trailer and broke open a case of bottled water, part of the cargo he was meant to deliver.

"I just took out the whole case and started handing it out to people, to keep them hydrated," he said from the truck. "You've got to survive, you've got to work together."

Another one of the people who had been stranded, Colin Stewart, left his home in Tottenham, Ont., around 2:30 a.m. Monday on his way to work in Wallaceburg, about four hours away.

Steward spent the next 25 hours stuck in his car, intermittently napping, phoning relatives and updating his Facebook page from his BlackBerry, the 50-year-old said Tuesday in a phone interview from his car.

The experience has been more boring than scary, he said.

"I've got about a quarter tank of gas I've turned on and off. I've got a nice big blanket I wrapped myself in," said Stewart.

"What can I do? I'm not impressed -- it's Canada."

Plows eventually cleared the stretch of road where Stewart was stranded and he headed straight to work, more than a day late.

While blizzards and highway closures are par for the course in the area, the results are rarely this severe, said Sarnia Mayor Mike Bradley.

"This has probably been the worst storm, and the most unusual one, we've seen in 25 years," he said.

The Blue Water Bridge to the U.S. was closed to truck traffic.