[gordner]

I am always amazed how quick people are to call someone a dumbass in this situation. He was not a dumbass the car started sliding unexpectedly. It is highly unusual for a stationary vehicle to start moving on it's own with no outside influence. He presumably had enough grip to walk around the car to remove the snow, I doubt any one here would have expected the slide either.
Two years ago a guy drowned under his vehicle on a Calgary city street, miles from any water and well above sea level. A flash flood ran down the road knocked his legs out from under him and trapped him undert the car leading to his drowning in 2 inches of water. Guess that guy was a dumbass too by internet standards.