A winter storm bringing snow and freezing rain Toronto and the American Northeast is responsible for dozens of flight cancellations in Montreal.

The storm reaches from Chicago to Washington D.C. to Boston.

By 9:30 a.m. about 2,600 flights to and from the affected cities had been cancelled.

The delays and cancellations are causing a cascade effect in areas outside the storm, such as Montreal.

Some flights headed to Toronto early Wednesday morning were forced to turn around and return to Trudeau airport.

Other airlines decided this morning to cancel all of Wednesday's flights heading for Toronto.

Aeroports de Montreal is warning travellers to make sure their flights have not been cancelled before leaving home.

Toronto and southern Ontario are expected to receive 10 to 15 cm of snow.