Dyatlov Pass

Two of the four found in the ravine had fractured skulls; one had crushing chest injuries consistent with high-force trauma, with little corresponding external wounding. Three of the recovered garments carried traces of radioactivity. One victim was missing her tongue, eyes, and parts of her lips — damage later attributed to decomposition and scavenging, though that attribution remains contested.

The radiation traces on at least three garments were noted by the 1959 investigation but not explained. Proposed sources include contaminated equipment from a prior expedition, proximity to Soviet nuclear testing in the region, or simple laboratory error. None has been confirmed or ruled out in any official investigation.

In 2019, Russia's Prosecutor General's Office reopened the case. Their 2020 conclusion attributed the deaths to a slab avalanche combined with reduced visibility and hypothermia — the hikers cut the tent to escape a collapsing snow slab and died of cold before they could return. The most technically rigorous version came from EPFL and ETH Zürich researchers Johan Gaume and Alexander Puzrin, whose 2021 paper in Communications Earth & Environment used computational modeling borrowed from automotive crash-test biomechanics to show that a delayed slab avalanche — triggered by the hikers' own cut into the slope, with katabatic wind accounting for the delayed timing — could produce the observed chest and skull injuries. It is the most coherent physical account produced to date.

A separate hypothesis, developed by journalist Donnie Eichar in Dead Mountain (2013), proposed infrasound: katabatic wind over the dome of Kholat Syakhl could have formed a Kármán vortex street generating low-frequency sound at intensities known to cause panic and disorientation in humans. It is not the leading explanation post-2021, but it has never been formally ruled out.

The Gaume & Puzrin model is careful and peer-reviewed, and it is also explicitly limited — the paper does not address the radiation traces on the clothing, and neither does the 2020 Russian reinvestigation conclusion. Avalanche researchers have contested the slope geometry and snow conditions at the site. The soft-tissue damage to one victim is attributed to decomposition and scavenging — plausibly, but without a definitive forensic basis from 1959. The classified Soviet-era file was only partially released; the completeness of the available record is unknown. The slab-avalanche account is the strongest physical explanation on record. The radiation, the investigator's own doubt, and the incomplete file are still there.