First major snowstorm of the season pummels southern Ontario

Saturday, December 14, 2013, 3:16 PM -

STORM WATCH: Tune into The Weather Network on TV for complete coverage on this system this weekend.

Canada's largest city was under a snowfall warning late afternoon Saturday as the first major winter storm in southern Ontario got going.

Communities from Niagara to Windsor and the Golden Horseshoe communities of Hamilton, Mississauga, Oakville, Burlington and Brampton were also under a warning, part of a system that will affect much of eastern Canada from Ontario and Quebec through to Atlantic Canada.

Highway traffic cams showed the same snowy scenes in the Hamilton-Niagara area as the storm began to roll in, and motorists reported slippery roads and poor visibility.

Rapidly worsening highway conditions were blamed for several collisions, including a pile-up involving around 20 vehicles that shut down the west-bound QEW between Winston Churchill and Erin Mills in Mississauga.

The Canadian Press reported no deaths or serious injuries arose from those collisions, and some motorists took shelter in fire trucks to keep warm.

Forecasters and authorities are warning drivers to stay off the QEW if possible.

Ontario Provincial Police are cautioning motorists to take care on highways, posting on Twitter: "IF YOU SEE SNOW, GO SLOW!''

The OPP says weather may have been a factor in a head-on collision that killed two people near Barrie, north of Toronto.

"Widespread snow, blowing and drifting snow will cause dangerous road conditions and slow travel along roadways," Weather Network meteorologist Brian Dillon warned. "Accumulations from Mississauga to Grimsby will likely be over 20-plus centimetres, with lake effect enhancement. Downtown Toronto will range from 15-20 cm of snow."

Dozens of flights through Toronto Pearson and Montreal-Trudeau airports were either delayed or cancelled.

In the GTA and other parts of the southwest, moderate system snow is expected to start around mid-day, with the full brunt of the storm coming in the evening - and for Ontario's capital, possibly becoming only the fifth 15-plus-centimetre December snowfall event since 1980.

By the evening, gusts of 40-60 km/h are expected in the storm, gusting higher by the lakeshore. 

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By Sunday morning, the heaviest snowfall will have reached the Ottawa area, still with strong winds, but it won't be over yet for the southwest. Lake effect snow squalls are expected to add another five or so centimetres to what could already be major amounts.

Winter storm warnings were in effect for the Niagara, Hamilton and Peel-Halton regions, as well as all of Eastern Ontario from Kingston to the Quebec Border, including Ottawa.

Quebec, in turn, was covered in winter storm warnings, including Montreal.

As for totals, areas along the shores of Lake Ontario will see relatively higher amounts, with the heaviest bound for the Golden Horseshoe and Niagara, although areas further north could also receive as much as 10 cm through the day into the evening.

Eastern Ontario, including Ottawa, will see the arrival of the snow later Saturday, intensifying through the night into Sunday, with potentially 20 cm or more in the forecast for much of the region.

Southern Quebec is also in the path of the storm, with Environment Canada predicting 15-30 cm beginning Saturday evening.

And beyond, the Maritime provinces were already covered with winter storm warnings, ahead of expected winter weather beginning Saturday night, with Newfoundland next on Sunday night.

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