I've explained the dynamics of it before, but I'm sure a lot of people didn't see it. Let's just say you are thinking WAY too small. Two extremely powerful low pressure systems (3 days apart) took the dream track for snow in the Puget Sound region. Major AR between the two systems with Arctic in place over the North Interior. It appears as if somewhere around 6 or 7 inches of water fell as snow in a 3 day period. Totally insane scenario that actually happened.
Don't forget the cosmos. Our planet is one little pea-sized marble suspended in a vast space. We'll be ok as long as other cosmic bodies keep their distance.