In reply to UKC/UKH Articles:
I broke my leg in Chamonix in winter, under the top of a chairlift, about 5m off the side of a piste, and getting from there to somewhere warm still took in the region of two hours. I had a down duvet in my pack and was pretty toastie (as far as memory can be trusted) in distinctly mediocre snowy weather, but without it I'm pretty sure hypothermia would have very quickly been added to the list of problems irrespective of the weather.
I'm not sure enough people are aware just how quickly cold will become a serious problem if they become immobilised in the hills.