I can't remember now which mountain man it was I read about that survived a blizzard by "building a cup full of fire, sitting around it cross legged (non P.C. term Indian style) wrapped a blanket around himself like a tipi" and weathered it out. I've always kept that little tidbit in mind living in an area where -40F isn't uncommon in winter. Always figured if I had to, my old fire dept bunker coat would be the best choice for the job.