A mistake, then vicious wind, then a tragic end...

[MDGross]

None of the hikers was a spy. No one was murdered. There was no coverup. Just hurried and inept autopsies combined with mind-boggling government bureaucracy and unfathomable laws.
On the night of Feb. 1, Tibo stands outside the tent; perhaps it's his turn to keep watch. Zolotaryov stands nearby visiting with his friend. Suddenly, the wind becomes dangerously strong. Tibo, in fact, is knocked down and begins rolling down the slope. Zolotaryov cries out for others to help before hurrying after Tibo. With their comrades in trouble, someone cuts the tent open so that they can exit quickly. As they leave the tent, others are knocked off their feet. More cries for help and now all nine are out on the slope. As fast as possible, those who have fallen are helped. But those who rolled down the slope struck rocks. Rustin and Tibo have fractured skulls; Lyuda and Zolotaryov have fractured ribs. Precious time can't be wasted trying to find the tent in the dark, so the five uninjured hikers help their injured friends to reach the shelter of the forest and find some protection from the wind. While Doroshenko and Krivonischenko build a fire, Igor, Zina and Kolevatov hurriedly dig out a snow den in an attempt to help their injured friends survive the night. There are only three injured hikers now, Rustin is not able to reach the forest and is the first to die. Kolevatov stays in the den to aid the injured; Igor and Zina decide to walk back to the tent, gather coats and shoes, and then return. They perish in their brave attempt. Doroshenko and Krivonischenko succumb to hypothermia. Unknowingly the snow den is built over a tributary and the poorly supported floor collapses. The four in the den tumble into the ravine below. In the weeks that follow, their bodies are covered with tons of snow, collapsing the chests of Zolotaryov and Lyuda. Tibo's skull fracture is made worse.
In retrospect, pitching the tent in such a vulnerable and unprotected location was a fatal mistake, though none of the hikers could have known about the wind storm to come.

[Osi]

I'm pretty close to your MDGross theory. I think I know there are a few young smokers in the group. Maybe a watch line, maybe a cigarette break outside the tent. The 3 people caught in the wind are the weakest individuals in the group in terms of weight. This puts your theory forward.

[GlennM]

MD and Osi, the scenario is very plausible, what concerns me is distance. Is it possible for someone to be swept up and blown at least the length of a city block before coming to rest?  There must be a point where it makes better sense to return to the tent than to go down hill. I would suppose 1/4 mile into a heavy headwind would be too far.  I think it would be natural to go with the wind. I think it would be natural to not split the group up. Finally, in a perfect world, I would imagine anyone caught in a hurricane force squall would drop to their knees and crawl back to the tent. What a mystery!