From what I understand, most places warn folks if the roads are icy and some places even have "ice days".
Those extra days off make it almost worth the hassle! ;-)
Last December, we had a couple of days where we got over a foot of snow - it was right during finals time for the semester, too! But we had almost a week off because of it, so some people just did grades based on work, plus we crammed exams in all over in rooms that wouldn't normally have been used and during the evening and early mornings. It was crazy!
Since I don't teach...I just got days off. ;-)