Stella Blue asked a great question and is getting solid advice. I don't want to hijack her thread, so I'm going to start one with a slight variation.

I spent a miserable, sleepless night up on Mt. Baldy on Friday night. I found a perch in the windbreaks which help around the head area but don't do much for the feet. I had a good pad and never felt cool from the ground. I had a 35 degree mummy bag and wore balaclava, thermal shirt, long sleeve shirt, down jacket and fleece. My upper body felt warm. The exposed part of my face felt very cold. My legs were ok-ish, but my feet were freezing. I dropped a chem pack down by my feet which has always worked like magic, but not this time.

I think two things were going on. One, this bag is just barely big enough for me, but if I'm not situated just right, my head and/or feet will tug against the stitches of the bag which means, I'm getting no loft in the tight, compressed area of the bag--this time, it was my feet that were compressed. As Harvey points out, with no loft, the passive heat retention system of the down bag couldn't do its work. The second thing that was going on was the wind kept sucking the heat out of the bag. I think my core was ok because my bag probably acted a bit as a protective layer, not letting the wind suck the heat from my down jacket and layers beneath, but I had no such under protection around my feet.

I was miserable--shivering and not sleeping the whole night, eventually, puking up my dinner and then wretching after that. (Probably a combination of altitude sickness, exhaustion and shivering.) At around 4 am, I was trying to think what else I could do and remembered that I had a mylar blanket in my bag. I then wrapped it around my feet on the inside of my sleeping bag. Fairly soon thereafter, my feet began to feel ok, but I continued to shiver until the sun came up.

A bigger bag with more room to keep loft would have been good. A tent, a bivy or even a trashbag to keep the wind off would have been good. What else would you have done to deal with the wind and conditions that I have described?

I welcome your criticisms and wisdom.

Brent N