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.