When it is winter in Ontario, it is very important to wipe the snow from your vehicle. Not just he windows, but also the hood, the roof and the back.
In the following video, you can see what happens when you do not clear the snow from your roof.
This driver had snow on his roof when he went onto the highway. The first time he hit his brakes, the snow slid off the roof and down onto his windshield. As he was in a middle lane at the time, he was in a precarious situation. He could not stop, nor he could not change lanes safely to pull off the road. This person’s laziness endangered the lives of himself and everyone else on the highway beside him.