I was not talking about sun burn, I was talking about snow burn. Snow burn is from when you fall and exposed skin slides over the snow surface in spring conditions. It's like a million little pins raking across your skin and it sucks big time. It also creates horrible raspberries. Covering up exposed skin that is likely to slide over the snow is the best defense. Aka, arms, legs, torso. We tend to protect our face pretty well, but if you are worried about that, a Darth Vader helmet should do that trick...
Sunscreen is also a good idea, the snow does reflect the sun and makes it a lot more powerful than your normal summer sun, but that isn't what I was referring too.