Police are working with emergency crews near Sarnia, Ont., to try and rescue motorists left stranded on a southwestern Ontario highway because of extreme winter weather.

More than 300 people were stuck along a stretch of Highway 402 near Sarnia because of heavy snow and high winds, Ontario Provincial Police said late Monday.

"The police were out for a while in their cars — but they too got stuck," reporter Heather Wright said. "So then we ended up with police and local firefighters on anything that would move in the snow, like all-terrain vehicles and snowmobiles."

She said the rescue teams then headed out to the highway and started shuttling people to safety.

Wright said the municipality set up four shelters to deal with people who couldn't get to their homes.

"There were countless more who just basically walked up to the nearest house where their car was stranded and said 'Could I stay for the night?' and people opened their homes to them."

Tracy Hunt, who made it off the highway and spent the night in a nearby office building, said she couldn't see anything when she got out of her vehicle.

"Each of us got out of our cars, we were talking amongst each other and you couldn't see anything — the houses around us, nothing," she said. "But then these folks came with a tractor and led us to where we are now."

OPP Const. Chrystal Jones said early Tuesday that plows were pulled off the roads on Monday, "so the snow is piling up."

There haven't been any serious injuries, but there were a couple of minor injury collisions, Jones said.

Emergency Management Ontario issued what it called a "red alert" for the area from Sarnia to London because heavy snowfall was causing zero visibility, while police recommended against any unnecessary travel between Sarnia and London.

"The Lake Huron snow squall that is closing roads and stranding motorists will remain west of the city of London until this afternoon when it will begin to shift," CBC meteorologist Johanna Wagstaffe said.

Wright said it wasn't snowing early Tuesday, but it was still windy.

"Right now the winds are up to 35 km/h, and they gust up to 65 km/h, and that's where the problem is because all the snow we've had is blowing around, making it really hard to see."

Lambton County Warden Steve Arnold declared a state of emergency at around 9:45 p.m. ET Monday, which allows authorities to ask the federal government for help.

The stranded motorists were advised to tune in to local radio station CHOK AM1070, FM 106.3 or FM 99.9 to get the latest rescue updates.

They were told to stay in their cars and pool vehicle resources until rescuers could reach them. They were also encouraged to make sure their car exhaust was clear of snow so fresh air would be supplied to the inside of their vehicles.