Provincial police are warning motorists in the Barrie and Orillia areas to drive with extreme caution as whiteout conditions are making driving treacherous.
Blinding snowdrifts slowed cars to 30 km/h on sections of Highway 400, while snowplows trying to catch up with fast-falling snow caused traffic delays.
Residents heading to ski hills in the region were being urged to be patient and take their time.
Environment Canada issued snowsquall warnings for the areas.
OPP Sgt. Cam Woolley said motorists were caught off guard with the blizzard-like conditions, especially those driving in from the Toronto area where skies were clear and sunny.
In the early afternoon, however, Environment Canada issued a weather bulletin, saying heavy flurries were expected to hit the Toronto areas at times.
Toronto's forecast on Saturday called for a high of -6C, but the wind chill was expected to make it feel more like -17C.
The city has been shivering through below-normal temperatures for more than a week, but has escaped the massive snowfalls that have buried areas near Barrie, Orillia and Owen Sound.
