My gaiters aren't winter specific and are just Cordura with velcro in the back with snaps and a tie at the top. Rick is right, get tall ones. I wouldn't bother with short gaiters in snow because the whole point is to keep your boottop and pant legs dry. Some winter gaiters have insulation in them like overboots to help keep your lower legs warm.

You could also look at something like Neo overboots.