I think on snow days you accept school isn't going to run as normal, and all staff report to their nearest school. Parents that want to keep their children off can do so, but those that don't can send them to school, where there will be staff to supervise.
It infuriates me that all my Facebook friends from the school I used to work at are already saying "hurrah, looks like a snow day on Monday, fantastic" while poor parents are thinking 'what the hell do I do now"