Residents of the city are struggling to dig out after a heavy snowstor buried Toronto.

A weather system that rolled into the GTA Sunday night could leave up to 15 cm of accumulation on the ground just in time for the Monday morning commute.

Environment Canada is calling for snow, which could be heavy at times, and blowing snow, before the morning rush hour.

The weather agency predicts anywhere from 10 to 15 cm of snow could fall before Monday’s drive.

Sgt. Kerry Schmidt of the OPP said Sunday afternoon that police in Burlington and Hamilton were “swamped” with reports of collisions, and he warned drivers to be careful.

Air travellers were being cautioned too. Pearson International Airport reported dozens of flight cancellations on Sunday and tweeted that passengers should check the status of their flights.

Billy Bishop Toronto City Airport, meanwhile, cancelled more than two dozen flights Sunday.

Porter Airlines, Billy Bishop Airport’s main tenant, said on its website that delays and cancellations are possible for those travelling to Windsor, Chicago, Boston, Toronto, Halifax, Moncton and Newark.

Meanwhile, temperatures are dropping and Toronto's chief medical officer of health has issued an extreme cold weather alert.

With the wind chill, it could feel as cold as - 25 C overnight, according to Environment Canada.

The weather agency says drivers can expect slippery road conditions and blowing snow that could make driving difficult on Monday morning.

Winds from the north east of 30 km/h could gust up to 50 km/h.

Dave Phillips, senior climatologist with Environment Canada, told CTV Barrie that most of the snow will avoid communities to the north.

"This storm, coming from Colorado, is heading more to the lower lakes, so areas north of Toronto are not going to be hit as hard," he said. "A little bit of a tough commute for tomorrow morning, but apart from that, we'll weather this one." - CTV News.