An avalanche caused the horrific deaths of nine students during a Siberian ski trip in 1959 – not aliens and yetis as some once believed, a new study reveals.
The discovery of their half-naked and mutilated bodies over 60 years ago fuelled bizarre conspiracy theories, from the paranormal to secret weapons testing.
Scientists from the Swiss Federal Institute of Technology (EPFL) created computer models to prove their theory that a slab avalanche caused their deaths.
The team showed that the ‘mystery of Dyatlov Pass’ in the Ural Mountains that saw nine experienced hikers killed – was down to a cut in the snow made by the group.
They had flattened a small section of the surface to form a ‘shoulder’ or ridge in the slope – believing it would shield them from the worst of the fierce winds.
A combination of other factors – including the unusual terrain and strong, icy winds – then triggered the ‘slab avalanche’ that chased the team out of their tent where they froze to death in -13F (-25C) temperatures.
The researchers hope the findings, published in British journal Communications Earth & Environment, could help avert avalanche disasters in the future.
The team showed that the ‘mystery of Dyatlov Pass’ in the Ural Mountains that saw nine experienced hikers killed – was down to a cut in the snow made by the group
Configuration of the Dyatlov group’s tent installed on a flat surface after making a cut in the slope below a small shoulder. This cut was the trigger for the slab avalanche that killed them
Professor Alexander Puzrin, of the Swiss Federal Institute of Technology (EPFL), Zurich, and corresponding author of the study, said the cut, combined with unusual terrain and a rare weather event called katabatic winds was enough to trigger the slab avalanche and kill the hikers.
The avalanche happened between nine and a half and 13 and a half hours after they made the cut in the slope – fitting evidence of the time of the accident.
Katabatic winds carry air down a slope under the force of gravity, transporting snow in the process.
This snow then accumulated up the hill from the tent due to a feature within the lay of the land where the crew had made camp – that they weren’t aware of.
Professor Puzrin said: ‘The katabatic wind probably drifted the snow and allowed an extra load to build up slowly. At a certain point, a crack could have formed and propagated, causing the snow slab to release.’
A slab avalanche occurs when the weak layer lies lower down in a snowpack. When it breaks off, the compressed snow on top is also pulled along the slope.
Co-author Dr Johan Gaume, head of EPFL’s Snow and Avalanche Simulation Laboratory, said: ‘We use data on snow friction and local topography to prove a small slab avalanche could occur on a gentle slope, leaving few traces behind.
‘With the help of computer simulations, we show the impact of a snow slab can lead to injuries similar to those observed.’
A manhunt was launched after the cross-country skiers failed to finish their 220mile-trek to Mount Otorten – translated in the local Mansi language as ‘Don’t go there’.
The scene that confronted rescuers was horrific. It led to speculation they had been attacked by extra-terrestrial beings – or yetis.
A manhunt was launched after the cross-country skiers failed to finish their 220mile-trek to Mount Otorten – translated in the local Mansi language as ‘Don’t go there’
This snow that came down as an avalanche accumulated up the hill from the tent due to a feature within the lay of the land where the crew had made camp
The latter notion stemmed from a fake newspaper headline found with stashed excess equipment that read ‘According to the latest information, abominable snowmen live in the northern Urals.’
The tongue and eyes of Lyudmila Dubinina, 21, and Semen Zolotarev, 38, were missing. Some victims – all young and fit – had fractured skulls and smashed ribs.
Led by 23-year-old Igor Dyatlov (pictured), the skiers failed to finish their mission, sparking a huge manhunt – all nine were found dead, many with unusual injuries
Simulation of the dynamics of a snow-slab avalanche and its impact on a human body. Injury levels in the simulation match those of the hikers
Others perished wearing only socks, or underwear, however, the reason the hikers left the tent unclothed remains unclear, study authors admitted.
The Swiss team also carried out 3D simulations of their injuries – which confirmed autopsy reports from the time of their discovery.
They had fled in terror – and run through the snow a mile or so down the mountain to where their bodies were found in the night time cold, not having time to dress.
Dr Gaume said: ‘And then, of course, there is the time lag between the team cutting into the slope and the triggering of the event. That’s the main focus of our article.
‘Previous investigators have been unable to explain how, in the absence of any snowfall that evening, an avalanche could have been triggered in the middle of the night. We had to come up with a new theory to explain it.’
Other unfounded rumours have included they had KGB connections and were killed by a Soviet missile on a secret mission to meet US agents.
Prof Puzrin and Dr Gaume make it clear that nothing can ever be proven. But their work may help prevent future disasters.
‘The truth, of course, is no one really knows what happened. But we do provide strong quantitative evidence that the avalanche theory is plausible,’ Puzrin said.
‘It will stand as a tribute to the ill-fated team who were confronted with a compelling force of nature.’
They had fled in terror – and run through the snow a mile or so down the mountain to where their bodies were found in the night time cold, not having time to dress
A combination of other factors – including the unusual terrain and strong, icy winds – then triggered the ‘slab avalanche’ that chased the team out of their tent where they froze to death in -13F (-25C) temperatures
The seasoned cross-country and downhill skiers – most of them from the Ural Polytechnic Institute – set off on the planned 14 day expedition on 27 January 1959.
The route was classified Category III – the riskiest – with temperatures falling as low as -22F (-30C) on the ill-fated night of February 1 into February 2, 1959.
The badly damaged tent was located a month later on the slopes of Kholat Syakhl – ‘Death Mountain’ – 12 and a half miles south of their intended destination.
Four of the bodies were not recovered for another two months after falling into a ravine – beneath a thick layer of snow.
Part of the reason for conspiracy theories surrounding the true nature of the ‘mystery’ was the fact the Soviet authorities hushed up their deaths.
The mysterious case has been the subject of books, documentaries, movies and computer games – including the Discovery Channel TV program called ‘Russian Yeti: The Killer Lives’.
The findings have been published in the journal Communications Earth & Environment.