TomD

I know you've been around the block a couple o'times and you have had a chance to work on your gear a lot. I think it might be a good idea to listen to the locals, and then sprinkle salt on what they say. Wool is really in up north for traditional reasons and because it always performs the same - sort of good, not great but consistently, especially over time. You can say the same about canvas and leather.

I really think it will be more critical to avoid moisture build up in those temperatures than the Sierra temps we are accustomed to, however balance moisture accumulation with the period of time we will be out.

I'm suggesting maybe a low tech day wear and a high tech camp wear for lazing around. Your big coat will be good, and down bibs would be awesome. Feet are gonna be a problem. Worse in day boots than in camp perhaps. Also I'm sure our gloves may not be adequate and we will need 40 below sleeping bags.

I did spent one night out in -40 degrees bivouacked at the base of the Eiger in Switzerland when I was 19 and I survived it - I think - oh no - maybe I died that night...

Jim