They aren't on single track, but they are riding some of the rrail trails we have: Hiawatha, Columbia Plateau

Winter road riding around here might as well be off road: they use sand and gravel instead of salt around here, and this time of years it can several iches thick at the edges of the road. This doens't seem to stop the Cat2 riders I know from getting out if the ice isn't too bad. Most of them keep a set of wheels just for the different conditions.

I.