I stumbled across mention of this incident last year. At first glance, it certainly looked like an eerie, other-worldly mystery ("they cut themselves out of the tent from inside!" "her tongue was missing!" etc, etc.) Yet after much study and thought, I've come to the conclusion that their tent was hit by a minor snow slide while they were preparing for bed that night. They must have known the tent had been hit but, unable to assess fully what had just happened and, perhaps fearing this was a prelude to full fledged avalanche, probably panicked and sliced through the tent wall to escape - without taking the time to dress properly for the frightful cold. At the edge of the woods the reality apparently set in and a few headed back to the tent - which they probably wouldn't have done had they been fleeing a murderous alien or government official. Alas, they didn't make it because of the cold, nor did any of the others.
