OPP are advising motorists to clean their windshields properly and drive slow as the snow continues to hit southwestern Ontario.

The snow forced the cancellation of all school buses serving the public and catholic, and french school boards.

Norfolk OPP sent out a photo after a driver was stopped with only a small portion of the windshield clelan.

"Please make sure your windshield and surrounding windows on your vehicle are clear before you put it into gear. How can you avoid something if you can't see it?" a Tweet from the OPP read.

The London region is under a special weather statement as up to 15 centimetres of snow is expected Friday, while areas like Chatham-Kent and Elgin County are under snowfall warnings with as much as 20 cm expected.

As well, a cold weather alert from the Middlesex-London Health Unit remains in effect until Saturday.