Snow is more forgiving than rocks & roots and things that find their way under our heaps. But it takes a skill that's not easy to identify. I've wheeled with someone who is a master at snow. His skill has everything to do with the lack of throttle. Not a swinging Richard sort of a guy. Finesse comes to mind.
That said, the "right" kind of snow is critical. Wet snow like we get here on the west side of the Washington Cascades isn't it. The dryer stuff typical of the dry side of Washington State, like where TjDave wheels a lot of the time, is what I'm talking about. Day & night. Day & night.
Given the opportunity to go "snow wheeling" with someone experienced at it is the place to start. Humility is high on the list, too. None of us know what we don't know, until we know it. And be prepared to screw up a lot! It's so much fun, just a whole different perspective on "wheeling"...effin' love it.