When my wife and I were climbing Kilimanjaro last year, both of our pads deflated and we were essentially sleeping on the ground one night at 11,000 feet and the next at 13,000 feet, until they could run replacement insulated pads up to us. There were closed cell mats under us, or it would have been a total fail.
“Hard to stay warm” doesn’t do that experience justice. Thank God we had good jackets and warm hats along to help us make it through the night.
Sleeping cold sucks. Sleeping cold at altitude double sucks.
A couple of years ago, I backpacked into timberline at 11,000' elev. It was mid-May and a cold front was moving in. I had a down sleeping bag rated at 5°, a Thermarest air mattress and a foam pad that was only 4' long. When I laid down to sleep I realized that there was a leak in the Thermarest. That short foam pad saved me from getting up in the middle of the night and packing out. Only my feet got cold, but I laid my backpack at the foot of my sleeping bag and used that to keep my feet warm.
