From “Birdleg’s” Appalachian Trail journal:

Separated from his party, Danish explorer and prolific author Peter Freuchen dug a trench in the snow to escape a blizzard. He lay in the trench and slept. When he woke, he found himself buried beneath the snow and a thick, ice-encrusted surface. He tried to sit up but the ice pinned him down. He clawed at the underside of his ice coffin until his frozen fingers were bloody, but he could not scratch it away. All his equipment lay uselessly above him on the sled. Without a digging tool, he was certain he would die. He carried absolutely nothing he could use as a tool…or did he? He slid his arms down the back of his trousers and defecated into his cupped hands. He quickly formed his own feces into a chisel shape, with a wide, slightly curved sharp end. He pulled it out into the cold air and it instantly froze as solid as steel. He dug his way out with a dung chisel. He ultimately lost one foot, but not his life.