Once, hiking in Grand Tetons Wyoming, we misjudged our hiking time, and realized we would not be able to get down the mountain before the nightfall. Fortunately we came upon a warming hut.
How lucky for us. It was large, with a heater and wooden benches. We spent the night there, in warm protected environment, and in the early morning hours finished our hike down the mountain. Thank goodness for warming huts.