A winter storm plowing through a large swath of southern Ontario caused widespread school closures and transportation disruptions Monday, and prompted some communities to cancel COVID-19 immunization clinics. As much as 50 centimetres of snow was expected in some areas, and the weather agency warned residents to be cautious given the risk of reduced visibility on the road.

Environment Canada issued snowfall, winter storm or blizzard warnings for a stretch of the province spanning from the Cornwall area to the east, the Algonquin region to the west, and the Niagara and London regions to the south.

The weather prompted many school boards to cancel school bus service and in-person classes just as schools were set to reopen following two weeks of online learning.

Dozens of flights to and from Toronto’s Pearson airport were also delayed or cancelled Monday morning, according to the airport’s website.

Toronto police shut down two of the city’s major highways, the Gardiner Expressway and the Don Valley Parkway, due to safety concerns.

“All ramps will be closed. This is to help move any existing vehicles that are stuck and allow snow plows to clear the routes,” police said on Twitter.

Another key Toronto-area highway was largely “barren” Monday morning because of the snow, Ontario Provincial Police Sgt. Kerry Schmidt said.

Schmidt posted several videos of Highway 401, showing a handful of vehicles stopped in the snow. “The only traffic that I see is vehicles that are stuck,” he said, adding even some tow trucks were stopped.

“This is the day you should’ve stayed home,” he said.

Public transit in the Toronto area was also affected by the weather, with the regional GO Transit network saying a number of its bus routes would be temporarily suspended or adjusted for safety.

The Toronto Transit Commission said customers should also expect longer-than-normal wait and travel times as the snow affects all its bus and streetcar routes.

A number of communities also called off COVID-19 vaccination clinics for the day in light of the weather. Clinics were cancelled in Niagara Falls, Stratford, Oshawa and across the Simcoe-Muskoka and Leeds, Grenville and Lanark health units.

Officials in Niagara Region said several other public facilities, including all regionally operated daycare and child-care centres, would be closed Monday.