Terminal burrowing can be identified in reports of hypothermia deaths, but has only recently been given a name. It is a behavior pattern observed in the last stages of hypothermia whereby the afflicted will enter small, enclosed spaces, such as wardrobes, cupboards, and closets.

Outdoors, the victim may burrow into piles of leaves, the crevices between rocks or fallen trees, or into culverts. Searchers must be aware of the possibility that the missing persons may be thoroughly hidden and too hypothermic to respond to their calls.

It is most often observed in moderately cold conditions, when the victim's body temperature falls slowly. These conditions would be found during power outages, or when someone is lost in chilly, but not freezing, weather.

See also Paradoxical undressing

--from Wikipedia