Cold and white

Winter is finally here. Last night we got 2-4 inches of snow, which means a few things. First, I got to spend 30+ minutes shovelling this morning. Secondly, it gives me things to ponder while I avoid grading algebra II quizzes. For example, how can it be cold enough to snow the aforementioned 2-4 inches, and yet the ice that covered the lake to the right actually melts?