Snow riding, at least on trails, requires low pressure (15lbs or so for a 150 lb guy) and wide tires (2 inch works) to get traction and control, and temps not much over 20 deg f for traction. Warmer than that and it starts to get a little squirrely. We ride trails that are packed and sometimes groomed. It's a blast. I've only done it twice, but I'm hooked.
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FB4K - Every October we wrench on donated bikes. Every December, a few thousand kids get bikes for Christmas. For many, it is their first bike, ever. Every bike, new and used, was donated, built, cleaned and repaired. Check us out on FaceBook: FB4K.
Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.