Christmas storm means a white Christmas for the GTA

A significant weather event will bring a mixed bag of Christmas Day weather across southern Ontario.

Environment Canada has upgraded its weather statement to a winter travel advisory for the GTA as heavy bands of snow will guarantee a white Christmas.

“Widespread snowfall is underway across south central Ontario this evening and will continue through the overnight,” said the weather agency. “Snowfall rates of 2 to 3 cm per hour may be possible at times, with a general total of 10 to 15 cm of snow expected by Friday mid-morning.”

A white Christmas is defined by Environment Canada as having at least two centimetres of snow on the ground.

The snowfall, which will be heavy at times overnight, will make driving conditions treacherous in some areas due to black ice and accumulation.

Much of eastern Ontario, including Ottawa and Haliburton, is under a rainfall or freezing rain warning. A total of 30 to 50 mm of rain is expected across most of the region with the showers easing and turning to snow flurries on Christmas Day. The heavy downpours could cause flash floods and water pooling on roads.

For areas in cottage country, freezing rain is expected to continue into Friday morning with as much as 5 mm of ice accretion. Local power outages may be possible due to ice build up.

Areas near Lake Huron, including London, Sarnia and Waterloo, are under a snow squall watch as steady winds could see upwards of 30 cm of snow in some areas.

“Visibility may be significantly and suddenly reduced to near zero,” said Environment Canada.