Toronto is under an Environment Canada snowfall warning.
The weather agency says rapidly accumulating snow could make travel difficult starting Wednesday afternoon thanks to a major storm headed toward Ontario and Quebec.
The heaviest snow in Toronto is expected to fall Wednesday night.
Total snowfall amounts near 15 cm are expected with peak snowfall rates of 2 to 4 cm per hour in the forecast.
The wallop of winter is likely to cause poor visibility for motorists, the national weather agency warned.
"Be prepared to adjust your driving with changing road conditions," the weather agency advised, with falling snow likely to impact the Wednesday evening commute.
The deluge is expected to continue through Thursday morning before gradually tapering off.
Snow may become mixed with ice pellets late Wednesday evening and overnight for some areas near Lake Ontario, Environment Canada said.
North and east of Toronto, continuing well into Quebec, what is being described as a "high impact storm" with up to 40 cm of snow in some areas is expected.
