Motorists in southern Ontario are being warned to be ready for poor visibility in snow and blowing snow today.
Environment Canada says visibilities in the south could be one kilometre or less in bursts of snow and blowing snow, with winds of 60 kilometres an hour.
Highway 402 has been closed in the Sarnia area after a crash involving 25 vehicles, including trucks, cars and a provincial police cruiser.
Police, fire and ambulance crews responded to the initial crash involving a transport and a car. There's no word on the nature of the injuries.
Police in the Chatham area are urging motorists to stay off the roads after a number of crashes, and part of eastbound Highway 401 has been closed. Roads have also been closed in the London area.
In Hamilton, police have closed a section of the Lincoln Alexander Parkway after a number of collisions.
Provincial police Const. Aaron McPhail says if people don't have to travel, they should stay put.
"We are just encouraging motorists that if they can postpone their trip to do so," Const. McPhail said.
"If they choose to drive, drive according to road and weather conditions and that they have an emergency kit and are fully topped up with fuel."