The moose liner like Bergstrom posted helps especially when you ride behind people and they are kicking up mud and snow. I can't think of the company but they are sell them at all my winter harescramble races, but they make a set like the moose ones only bigger. You could do heated grips. What I do during my winter mud scrambles is get some rubber gloves (like what Dr.s wear) and get next to a heater w/ my regular riding gloves, get them all toasty along w/ my hands all nice and toasty, right before the race. Once everything is toasty, I slip on the rubber gloves and then immediately the riding gloves. IDK why but for some reason this helps a lot but you have to be sure to keep moving, b/c w/ the rubber gloves you will work up some sweat in there and if you sit around and not do anything, you will eventually get cold, this causing the sweat to litterally want to freeze on ur hands. Just a thought.