Gusting winds and snow-filled roads are creating treacherous driving conditions for motorists across parts of southern Ontario.

A snowfall warning issued for Toronto by Environment Canada on Wednesday has ended, but the national weather agency is warning that strong northeast winds will persist through to about mid-evening, leading to blowing snow and reduced visibility.

"Travellers should thus be prepared for poor driving conditions due to snow-covered roads, along with reduced visibilities in falling and blowing snow. Consider postponing travel until conditions improve," Environment Canada said in a statement.

Snowfall warnings issued for the Niagara, Kingston-Prince Edward, Brockville and Belleville areas has also ended.

Environment Canada says up to four centimetres is possible for regions in eastern Ontario, and the temperature in Toronto is expected to drop to a low of -16 C on Wednesday.

The City of Toronto is urging motorists to stay off the roads if possible, as crews work to plow the highways and main routes.

The treacherous road conditions have caused a number of collisions. During the Wednesday morning commute, the highways in the GTA at one point were averaging one crash every minute, OPP said.

East of Toronto, a major pileup on Highway 401 near Napanee, Ont., temporarily closed the westbound lanes. More than 150 vehicles were involved in crashes in the region.

In Trenton, Ont., the westbound lanes between Wallbridge-Loyalist and Glen Miller remain closed due to a crash involving a number of tractor trailers.

The City of Toronto has issued a cold weather alert, triggering an increase in services available to vulnerable residents.

The city's manager of road operations said crews will begin clearing residential streets Wednesday afternoon and the job will likely take up to 18 hours to complete.

In the meantime, property owners are being reminded to clear their sidewalks and motorists are advised to drive cautiously.

The weather is also a factor for those opting to take public transportation. Both GO Transit and TTC streetcar riders have been told to expect delays.

The TTC said its Scarborough RT service will remain suspended so that work crews can clear ice and snow from the tracks.

Some GTA-area school boards have cancelled transportation services.

  • For a full list of closures and cancellations in Toronto, click here.

For the lucky few hoping to fly out of the city, there are several delays and cancellations due to the weather here and in other cities across Canada and the U.S.

Air travellers are advised to check their flight status before heading to the airport.