On Feb. 1, 1959, nine students died while on a ski trip in Russia's Ural Mountains. Though their bodies were recovered, the mystery of how they met their end has persisted for 62 years. Now, researchers say they may have determined the cause of what's known as the Dyatlov Pass incident: a "bizarrely" small slab avalanche, reports National Geographic. Diaries recovered at the scene indicated the group cut into the slope of Kholat Saykhl, creating a flat surface on which to set up their tent on Feb. 1. When searchers reached the tent it was almost entirely buried in snow and had been cut open from the inside; the bodies were found in various places down the mountain, some with broken bones and skull fractures. The avalanche theory has long been argued, and a Russian reinvestigation upheld that theory in 2020, Reuters reported at the time. But there seemed to be holes. More:
- The slope where the tent was pitched wasn't steep enough to generate an avalanche; there was no new snowfall on Feb. 1 that would have caused a collapse; and the victims didn't asphyxiate, as is typical. There was also the question of timing: When the group cut into the slope they formed a slab of snow up slope from them. If that slab was unstable, the expectation is that it would have given way immediately, but forensic data suggests it didn't fail for at least 9 hours, reports the New Scientist.
- Alexander Puzrin, a geotechnical engineer working in Switzerland, and Johan Gaume, head of the Snow Avalanche Simulation Laboratory in the same country, investigated. Their findings, published in Communications Earth and Environment, "show the plausibility of the avalanche hypothesis" for the first time, Gaume tells LiveScience.
- They discovered Kholat Saykhl's slope is deceptive. LiveScience reports that while the slope in the area is an average 23 degrees, in the location of the tent it was 28, near the roughly 30-degree conditions needed to cause an avalanche.
- The diaries reported strong winds that night, which Puzrin and Gaume believe were katabatic winds that would have carried plenty of snow from higher up to their tent, adding to the load and finally triggering the avalanche many hours later.
- Computer simulations suggested the avalanche would have been quite small, the release of a slab of snow perhaps 16 feet long, explaining why the search team didn't find evidence of an avalanche: the snow would have filled in the area the group had cut out and then been masked by fresh snowfall.
- To explain the injuries, they turned to car-crash research on cadavers General Motors did in the 1970s and determined that because their beds were made on their skis, the impact of the snow against the hard surface beneath them could have broken bones but wouldn't have been fatal.
- But as the New Scientist notes, not everyone is on board with the theory. Count Jim McElwaine of Durham University among them. "It doesn’t explain why these people, after being hit by an avalanche, ran off without their clothes on into the snow. If you're in that type of harsh environment it’s suicide to leave shelter without your clothes on," He says. "For people to do that they must have been terrified by something. I assume that one of the most likely things is that one of them went crazy for some reason."
(Read more Dyatlov Pass incident