Arctic explorer frees himself from a snowy grave using … his own feces?

On one of his many expeditions, Freuchen was trapped, after an avalanche buried him alive. His foot had gotten stuck and he couldn’t move it, the cold was becoming more and more unbearable and he was beginning to suffer the first effects of hypothermia.
Freuchen tried every possible way to get out of there, but he couldn’t feel his foot, and…