This is known as the Dyatlov Pass Accident (though it has more of an “incident” feel than an “accident feel”–I mean, there’s no indication that anything wasn’t done deliberately).
The problem, of course, with mysteries like this is you have no way to know which of the various details is real and which is embellishment. The avalanche story sounds good but then you’d think that’d have been the official explanation. Plus, there’d be lots of snow right?
Something to chew on.