If you ever have or think you might have to deal with frostbite... then here's a link to an interesting American Alpine Club article about the essentials of frostbite... http://publications.americanalpineclub.org/articles/13201213440/Essentials-Frostbite

A good article, thanks Paul.

Another article regarding prevention:  http://www.climbing.com/skills/prevent-and-treat-frostbite/

(I like the windchill chart at the bottom.)

When skiing when it's windy or very cold, I'll often put on my face mask.  Makes for goofy photos on the day but happier nose and cheeks the days following.