Elk will eat snow if they get thirsty enough, don't know if I've ever seen any documentaion that supports snow eating by whitetails though.

In the areas of northernPotter and Tioga countiesthat I'm familiar with, there are many spring seeps of various sizesback in the woods, that should offer some water almost all winter long. My uncle's farm across the valley from my camp, got its water from a pasture-bank spring (old cast iron ram pump),for many years before uncle had a welldrilled.

That largespring never froze, wasn't unusual to see deer out there gettin' a drink just75 yards from the barn, in very cold weather.