Schools are closed and commuters are facing delays across southern Ontario as snow and heavy winds continue to hammer the area.
Environment Canada says regions including the Greater Toronto Area, Kitchener and Hamilton are expected to see up to 30 centimetres of snow into Thursday afternoon.
Toronto, York, Peel and Halton Region schools are closed today, and post-secondary schools including the University of Toronto, Toronto Metropolitan University and York University say their campuses are closed.
Environment Canada says the Ottawa area will see up to 25 centimetres of snow, tapering off Thursday evening.
The weather agency adds that northerly wind gusts of up to 60 kilometres per hour will result in blowing snow and reduced visibility, and a sharp temperature drop will cause cold wind chills.
Provincial police are advising residents to stay off the roads if possible, as officers have responded to dozens of collisions since 5 a.m.
At Toronto's Pearson airport, officials say air traffic management procedures are in place due to the weather, impacting some arriving and departing flights.
Travellers are advised to check their flight status before coming to the airport, where snow clearing operations are underway.