I worked on the flightline (no trees/bushes) in the UP of Michigan, so I have a little experience here. We/I also did a lot of testing for new or upcoming polar gear for the military.
Here's my bit part on surviving in -60 degree weather:
- Stay dry (don't get wet, and avoid sweating)
- Stay out of the wind, even if a breeze
- Utilize many layers (including on your hands and feet)
- Don't drink alcohol
- Avoid any sort of chemical reaction heat warmer doohickeys. They heat up real nice, which causes you to sweat, and in those kinds of temperatures they don't stay warm but for a few minutes.
- Avoid any neoprene polar gear (we tested a bunch of this for body, hands, and face). It doesn't keep you warm, and its not breathable, so again, you sweat. It's unsuitable.
- And lastly, find the nearest diesel engine or bonfire ASAP
When the temps got in the realm of -60, diesel engines stop wanting to run (our trucks ran 24/7), even with their grills covered.
We would wear:
Head: baclava with two layers of wool with a layer of gortex between them, one of those funny mil issue russian style flight hats (the silvery ones that made you look like you had snoopy ears) on top of that.
Torso: The mil issue polar suits (they looked like really heavy duty carrhart deals)
Hands: flight gloves (I believe SOF guys fancy these), oversized mil issue wool gloves over these, and the mil issue polar mittens over these.
Feet: 2-3 layers of socks (the innermost layer a thin wicking sock, the outermost thick wool). "Bunny" boots over these, or "muckalucks"
Much of the time we were out there without a heat source and this kept us uncomfortably alive.
If I were in an alpine environment, I would get out of the wind, build a snow cave and try to build a fire (I *always* carry a lighter, even though I don't smoke). I would saw off every bough I could get my Leatherman Wave on (which I also carry everywhere. I also have a spare Gerber multitool in my pack).
I know this goes against what is taught in alpine survival schools, but I would avoid eating snow (and cold water, if at all possible). I was stupid once (just once!) and got myself in a hairy situation during a climbing trip and had to rely on eating snow for hydration and I believe it was helping me go hypothermic. Paradoxal undressing is a hard thing to fight, especially when your brain is scrambled. I had hiked this mountain many times before and it was considered easy. But I left too late and didn't check the weather reports (two extremely stupid mistakes).