A snow squall warning is in effect for Barrie, Collingwood, Orillia, Midland, Coldwater, Orr Lake, Hillsdale, Lagoon City and Washago.
Under the snow squall bands, visibility will be significantly reduced due to heavy and blowing snow that will quickly accumulate, the federal weather agency says.
The squalls are predicted to take place into Friday night.
According to Environment Canada, a snow squall is currently extending from from Georgian Bay to just north of Barrie and into Lake Simcoe.
Snow squalls are expected to intensify and increase in coverage Thursday afternoon and will continue through Friday night in some areas.
“Travel will be hazardous at times, and motorists are advised to change their travel plans accordingly,” Environment Canada said.
“Local whiteout conditions may occur.”
If visibility is reduced while driving, Environment Canada says motorists should slow down, watch for tail lights ahead and be prepared to stop.
Public Safety Canada encourages everyone to make an emergency plan and get an emergency kit with drinking water, food, medicine, a first-aid kit and a flashlight.