Well it is the season for this topic, at least here in Canada and the northern U.S.
(I have modified these from http://idioms.thefreedictionary.com/snow)

To be (as) pure as the driven snow:

Pure and chaste (Often used ironically.)
E.g. Jill: Sue must have gone to bed with every man in town. Jane: And I always thought she was as pure as the driven snow!

A snow bunny:
1. Someone learning to ski.
E.g. This little slope is for snow bunnies. They call it the ‘bunny hill’.
2. A young, attractive female at a skiing lodge.
E.g. Some cute little snow bunny came over and sat beside me. This place is swarming with snow bunnies that have never even seen a ski.

Snowed in:
Trapped (somewhere) because of too much snow, most likely due to a recent snow storm.
E.g. The snow was so deep that we were snowed in for three days. Luckily we had enough food to last us a while.

Snowed under:
Overworked; exceptionally busy.
E.g. Look, I’m really snowed under at the moment. Can this wait?

A snow job:

An attempt to persuade or deceive someone by praising them or not telling the truth.
E.g. Dane will need to do a snow job on his Dad if he’s ever going to borrow the car again, after getting into so many fender-benders (minor car accidents).

Enjoy and stay warm!