Heavy snowfall took its toll on southern Quebec Tuesday, with more than 10 cm of snow falling before dawn, and 30 centimetres by nightfall. An additional 5 to 10 centimetres of snow is expected to fall before the storm passes through.

CTV weather specialist Lori Graham said Montreal and the St. Lawrence Valley are likely to see 20 to 30 centimetres accumulate, while the Eastern Townships could see a total of 50 centimetres of snow lying on the ground at storm's end.

During the day Tuesday wind gusts of up to 50 kilometres per hour will blow that snow everywhere, making driving difficult.

Transport Quebec reported numerous crashes during the morning rush hour as cars and trucks slid off the road or into each other.

The heavy snow also delayed trains and buses, with passengers saying some trains coming into Montreal were stuck on the tracks for 20 to 40 minutes.

The AMT reported that its Lucien L'Allier station was overcrowded, and that trains heading east were slow to depart the station. The delays got longer during the morning as trains converging on the downtown station ran into congestion.

Long-distance bus lines, such as Orleans Express, said all trips were being made but could be cancelled if conditions worsened.

Dozens of flights in and out of Montreal's Trudeau airport were delayed or cancelled. Flights leaving for anywhere from Chicago to the Maritimes faced delays, while flights to areas where the snow was heaviest, such as Minneapolis, Boston, Toronto and Ottawa, were cancelled.

Dozens of flights in and out of Trudeau Airport were cancelled or delayed.

Many schools, especially those west and south of Montreal, decided to cancel classes for the day.