I think Igor B's theory would benefit from an English translation and all of these explanations being collected in one place. As far as I know it's currently over on an other forum spanning thousands of posts.
I have read several pages but never found the part that explains the injuries... also there are 7000 posts(?) in that thread and some are Russian memes, etc. Very hard to untangle.
The lead goes nowhere. Occams razor is best. No blast, just unprotected falls explain injuries.
To me, Occam's razor says that it can't be a fall. People who fall end up landing on one of their extremities, and break their legs, arms, head. It's very hard to fall on your chest (and not break your head). The probability of this happening to two people.. practically zero. Something falling on them however, much better explanation.
That said I'm not necessarily in favor of the tree fall theory, because who lifted the tree then? It also doesn't explain why those who weren't injured by the tree all died. Maybe I'm thinking about this incident in an different way than others... but the very fact that they all died, in proximity, and at around the same time, is a very unusual circumstance. Cold affects people differently, depending on amount of body fat (varies by gender), how they are dressed, etc. Occam's razor says some of them should have survived or at least survived for much longer than others, and it was cold, the instinctive thing to do is to keep moving. Some should have been found miles and miles away. In the Auspiya valley looking for the labaz, or looking for the Mansi hut they passed. Or even further.