Snow continues to build up across the GTA as a large winter storm system settles in over southern Ontario.

Toronto and most of the Greater Toronto Area currently sit under a special weather statement from Environment Canada, with 10 to 20 centimetres of snow expected locally tonight.

Hamilton, Niagara, Oakville and Burlington are under a winter storm warning and parts of the region could see as much as of 30 centimetres of snow by Tuesday night.

“It’s part of a massive system. Right now the centre of the storm is back down in the American Midwest but that particular part of the storm is going to weaken off tonight and be taken over by another system developing on the eastern seaboard of the U.S.,” Environment Canada Meteorologist Geoff Coulson told CP24 Monday evening.

“That’s the one that’s going to continue keeping the snow in the GTHA overnight tonight and during the day on Tuesday. The biggest impacts at this point will be in the western part of the GTA and we still do have winter storm warnings in effect in areas from Hamilton down into the Niagara Peninsula.”

Snow began falling Monday afternoon and is expected to continue until early Wednesday morning, Environment Canada said.

By Monday evening the precipitation was already causing delays on the roads, with GO Transit cancelling some bus routes and reporting lengthy delays on other routes.

City salt trucks were out on the roads throughout most of the day, salting arterial roads, bike lanes and sidewalks ahead of the storm.

Sheridan College also said it was shutting down at 5:30 p.m. due to the weather. The college said that all evening classes are cancelled tonight.

Messy commute expected Tuesday

With the snow expected to continue into Tuesday and Wednesday, the commute could be messy Tuesday morning as well and police are advising motorists to leave extra time to reach their destinations.

“The heaviest snow is expected to fall through the overnight hours into Tuesday morning,” Environment Canada said in its advisory.

“While total snowfall amounts of 15 to 25 (centimetres) are expected, some areas in the Hamilton and Niagara corridor could see locally higher amounts of 30 centimetres.”

During the inclement weather, Environment Canada is advising motorists to consider rescheduling all non-essential travel.

“Winds gusting to 60 kilometres per hour are also expected this evening into Tuesday resulting in widespread blowing snow. Travel conditions may become hazardous as a result of snow and blowing snow,” the advisory continued.

“There may be significant impact on rush hour traffic in urban areas. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.”

Coulson said the heaviest snowfall amounts on Tuesday are expected in Burlington and St. Catharines. He added that the accumulation is expected to be greater in western parts of the region.

“For eastern parts of the GTA, probably just a few centimetres on the ground – they’re not going to have all that much to worry about,” Coulson said. “But as you get into downtown Toronto, toward the west part of the GTA, we could have on the ground upwards of four to five centimetres and that snow will continue to fall during the day on Tuesday.”

“So again, total accumulation in the eastern part of the GTA by Tuesday evening, more like 10 centinetres total. But as you get closer to the western part of the GTA, more like 15.”

The storm is expected wind down and pull away on Tuesday evening.