Clearing Off the Car
Remember, when driving, the snow on your car will remain completely stationary and will not blow off on drivers around you. Also, your rear window defrost is more or less the temperature of lava, and will melt any amount of snow.
Therefore, this is the maximum amount of snow you should remove from your car.
Remember this picture:
That which qualifies as poor parking in the summer is exactly how you should park when a small amount of snow is covering the lines during the winter. Particularly when parking in a mall on Christmas Eve to minimize the number of people that can park in actual parking spots.
Remember, your car is substantially larger in the winter than it is in the summer, so you absolutely need to make sure not to park in spots you've been using for the past six months.
The day before the first snowfall of the year
The first snowfall of the year
As soon as the snow stops actually falling from the sky
The second another snowflake touches the road
Every snowflake is unique, which means every new snowflake is a new metal-rending, bone-splintering, havoc-inducing piece of frozen water. It is imperative you forgot all the driving experience you've gained during each winter in which you've driven, and safely panic on the roads with everyone else driving two cars wide on a four-lane highway.
Remember, although rare, if you live in Canada, you may need to drive in winter conditions. You'd think it would be as simple as driving like you would the rest of the year, but with slightly more caution, but you'd be wrong. Panic, and panic hard. The world is ending. Until at least April.