The Dyatlov Pass Incident

Despite sixty-plus years of speculation about the deaths of nine skiers in Russia's Ural Mountains in 1959, the "Dyatlov Pass incident" remains an unsolved mystery.

Published Dec. 28, 2017

Updated Jan. 29, 2021
 (Wikimedia Commons)
Image courtesy of Wikimedia Commons

In 1959, the frozen bodies of a nine-member ski-hiking expedition that had gone missing weeks weeks before in northern Urals of the Soviet Union were found near their campsite on a mountain called Kholat Syakhl (which, according to Russian sources, means "Dead Mountain" in the indigenous Mansi language).

Made up mostly of students and graduates from the Ural Polytechnic Institute a few hundred miles away in Yekaterinburg (then called Sverdlovsk), the team had set out on 27 January to reach another mountain about 7 miles away, Gora Otorten (which means "Don't Go There" in Mansi). After being sidetracked by a snowstorm, they pitched a tent on the eastern slope of Kholat Syakhl on 2 February. That night they died. Apart from the fact that they froze to death, no one knows why.

Police and military investigators charged with solving the case were baffled by what they found. The skiers' tent had been sliced open from the inside and hurriedly abandoned. Their belongings were still inside, but the skiers weren't. The placement and condition of their bodies, some found as far as a kilometer-and-a-half (almost a mile) from the tent and buried under four meters (13 feet) of snow, were odd — to say the least.

An April 2013 article in the The Telegraph described the grisly scene:

Investigators found footprints in the snow of eight or nine people who were wearing socks, a single shoe or were barefoot. The footsteps led towards a dense forest but disappeared after 500 metres.

The first two bodies, of two men, barefoot and dressed only in their underclothes, were found at the edge of the forest near the remains of a fire. The next three bodies — of [expedition leader Igor] Dyatlov and another man and a woman — were found between the fire and the tent, suggesting that they had been trying to return to the tent. Autopsies failed to find any evidence of foul play. An inquest concluded that all five had died of hypothermia.

Two months later, however, the partially-dressed bodies of the other four members of the team were discovered in a forest ravine, not far from the first two bodies. They appeared to have suffered traumatic pressure or crush injuries, and the tongue of one had been ripped out. Otherwise there were no external injuries, but tests conducted on their bodies and clothing showed small traces of radiation.

The investigators concluded, enigmatically, that the skiers died because because they encountered a "natural force they were unable to overcome." Public access to the site was banned for three years. The results of the investigation were classified.

If ever there was a sure-fire recipe to whip up rumors and conspiracy theories, this was it. The conclusion was vague. The evidence was under lock and key. There were too many questions left unanswered.

Why, for example, did the skiers flee the relative safety of the tent? Why did they leave their belongings (including warmer clothing) behind? Why did some of them simply freeze to death, while others showed signs of internal trauma? Who or what removed the tongue of one of the victims? Why were there traces of radiation on their clothing?

And what about the UFOs?

Fireballs in the Sky

It was reported that eyewitnesses in the northern Urals saw fast-moving "balls of fire" in the night sky around the time of the Dyatlov Pass incident. It has been suggested, plausibly, that these were Soviet missile or rocket tests. But another theory — and here we encounter the earliest paranormal explanation of the incident — holds that the fireballs (whatever they in fact may have been) exploded or emitted a beam of unspecified "energy" that directly caused the skiers' deaths.

That theory was proposed 31 years after the fact, oddly enough, by one of the original investigators in the case, a former public prosecutor named Lev Ivanov. But Ivanov's fireball theory presupposes that the reported sightings match up with the actual date of the incident (2 February), an assumption that has been challenged by another author, Russian mountaineer Evgeny Buyanov, who says he found no verifiable reports of unidentified flying objects in the Urals on those dates.

Before Ivanov's 1990 article came out, the predominant explanations for the Dyatlov deaths focused on straightforward natural causes — avalanche or animal attack, for example (human attack, though not impossible, was ruled out by investigators for lack of evidence) — or secret government activity, such as a military or KGB operation the skiers unknowingly stumbled upon. Despite the declassification and release of the case files in the intervening years (the contents of which were eventually published online), the original documents did little to resolve lingering quandaries, and in fact only seemed to prompt further outlandish speculation.

The Yeti Hypothesis

The most outlandish hypothesis to date was that proposed in a June 2014 Discovery Channel "documentary" called (spoiler alert!) Russian Yeti: The Killer Lives. This is from the press release announcing the show's first airing:

On February 2, 1959, nine college students hiked up the icy slopes of the Ural Mountains in the heart of Russia but never made it out alive. Investigators have never been able to give a definitive answer behind who -- or what -- caused the bizarre crime scene. Fifty-five years later, American explorer Mike Libecki reinvestigates the mystery -- known as The Dyatlov Pass incident -- but what he uncovers is truly horrifying ...

Following the trail of evidence, Mike finds proof that the hikers were not alone -- a photograph, taken by one of the hikers a day before they died that suggests that they encountered a Yeti.

Yes, you read that right. According to the Discovery Channel, the Dyatlov group met their deaths at the hands of a Yeti, also known as the Abominable Snowman (or, if you prefer, Bigfoot's Asian cousin).

It has long been rumored that Yeti-like beasts inhabit the wilds of Siberia and the Ural Mountains to the west, although, like everywhere else these so-called hairy hominids have allegedly been sighted, no one has come forward with verifiable evidence of their existence. Nevertheless, the show's host, Mike Libecki, said the Dyatlov Pass incident proves they're real.

"When I found out one of the students was missing a tongue immediately I knew this was not caused by an avalanche," Libecki said. "Something ripped out the tongue of this woman."

That something, Libecki naturally concluded, could only have been a Yeti. As further evidence, he presented an alleged photo of the Yeti (displayed in the tweet below) snapped by a member of the Dyatlov expedition:

Yet no matter how many times one hears the out-of-focus figure described as a "Yeti," or a "creature," or something other than human, the fact is that it resembles nothing so much as an ordinary, adult male human being. And no matter how many times one repeats the claim that the only reasonable explanation for one of the Dyatlov bodies missing a tongue is that a Yeti pulled it out, it pales beside the straightforward hypothesis that her tongue was devoured by a scavenging animal or decomposed due to constant contact with the stream of running water where the body was found.

In any case, it wasn't just the tongue that was missing. According to the Dyatlov autopsy reports, also missing was some soft tissue around the woman's eyes, eyebrows, nose bridge, upper lip, and cheek bone -- not to mention the eyes themselves.

The problem with proposing Yeti attacks and killer UFOs as the answer to the Dyatlov puzzle is obvious: They render it more mysterious, not less. And while isn't entirely implausible that secret government shenanigans were in play (we are talking about the Cold War-era Soviet Union, after all), even that is speculative overreach insofar as it is based on assumptions, not evidence.

The Infrasound Hypothesis

The same applies to some of the putatively scientific explanations offered up in recent years. Author Donnie Eichar proposed in his 2013 book Dead Mountain: The Untold True Story of the Dyatlov Pass Incident, for example, that the skiers may have been driven to hysteria by infrasound waves caused by a weather phenomenon known as a Kármán vortex street.

In simplest terms, a Kármán vortex street is an oscillating pattern that emerges when a fluid or gas (in this instance, wind) flows around a suitably-shaped object (in this instance, a topographical feature: the mountain). When they occur on such a large scale, these wind patterns can theoretically generate very-low-frequency sound waves that have been blamed for harmful physiological and psychological symptoms in human beings. According to a 2001 review of the medical literature by the National Institute of Environmental Health Sciences, such symptoms range from annoyance to fatigue to nausea.

Eichar argues that just such a phenomenon may have occurred under extremely high wind conditions on Kholat Syakhl the night of the incident. The resulting bombardment of the skiers by infrasound waves induced severe panic and caused to flee the safety of their tent and meet their deaths.

But never mind the what-ifs entailed in supposing that the wind interacted with the dome of Kholat Syakhl in just such a way as to produce the low-frequency sound effects required, the fact is that acoustic scientists are far from sure that infrasound exposure causes even the mildest symptoms that have been attributed to it, much less extreme panic.

The Avalanche Hypothesis

We don't pretend to have the solution to the Dyatlov mystery, but some of the facts of the case point to an explanation that doesn't require such a colossal leap of faith.

One thing we do know induces panic in people on a snow-covered mountainside is an avalanche. And while the number of skiers and hikers known to have been killed by infrasound waves to date is zero, avalanches are known to kill approximately 150 skiers, snowmobilers, and snowboarders worldwide every year, according to National Geographic. Moreover, the crushing weight of the four meters of snow under which the last four bodies in the Dyatlov group were found -- possibly deposited there by an avalanche -- could account for their internal injuries.

According to meteorological data compiled by Evgeny Buyanov, temperatures in the vicinity of the skiers' Kholat Syakhl campsite dropped precipitously from minus-11 degrees C to as low as minus-25 degrees C on the night of 1 February 1959. Wind speeds are estimated to have reached between 8 and 16 meters per second, with gusts likely even higher. Without adequate protection, frostbite, hypothermia, and death are virtually guaranteed under such conditions, and within a very short period of time.

Autopsy reports say the proximate cause of death of all but one of the Dyatlov victims, even those who suffered internal trauma, was hypothermia. Did an avalanche occur? We don't know, but one could have, and could account for some unexplained aspects of the incident, including why the skiers fled their tent and why some sustained the kinds of injuries they did.

One may object that an avalanche doesn't explain everything -- the radioactivity found on some of the bodies, for example. Granted. But neither does a Yeti attack, a Kármán vortex street, nor, given that we don't even have proof that they were in the vicinity when the skiers met their fate, do unidentified flying balls of fire.

Update: In January 2021, the avalanche hypothesis garnered scientific support via a study that used computer modeling to simulate the effects of a particular kind of snowslide event called a "delayed slab avalanche." The research demonstrated that a small but deadly avalanche could have occurred despite the absence of certain conditions that normally precede such an event, and even explained how the victims could have sustained the some of the strange, atypical injuries that were found.


Buyanov, Evgeny and Boris Slobstov.   "The Mystery of the Death of the Dyatlov Group."     Mountaineers of the Northern Capital, 2002.

Eichar, Donnie.   Dead Mountain: The Untold True Story of the Dyatlov Pass Incident.     San Francisco: Chronicle Books, 2013.   ISBN 9781452129563.

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Jaekl, Philip.   "Why People Believe Low-Frequency Sound Is Dangerous."     The Atlantic.   19 June 2017.

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Osadchuk, Svetlana and Kevin O'Flynn.   "The Dyatlov Pass Incident."     Fortean Times.   February 2009.

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Radford, Benjamin.   "The Yeti: Asia's Abominable Snowman."     LiveScience.   27 November 2017.

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Discovery Channel.   Russian Yeti: The Killer Lives.     June 2014.

Discovery Press Web.   "Discovery Channel Heads Deep into Siberia in Search of Russian Yeti on Sunday, June 1."     1 June 2014.   "Dyatlov Pass Incident."     Accessed 28 December 2017.

National Geographic.   "Avalanches."     Accessed 28 December 2017.

National Institute of Environmental Health Sciences.   "Infrasound: Brief Review of Toxicological Literature."     November 2001.

The Siberian Times.   "Artist Claims He Had Close Encounter with Yeti."     20 August 2015.

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The Telegraph.   "Yuri Yudin."     27 April 2013.


[UPDATE Jan. 29, 2021]: Updated with news of research showing a delayed slab avalanche could plausibly account for some of the heretofore unexplained features of the incident.

David Emery is a West Coast-based writer and editor with 25 years of experience fact-checking rumors, hoaxes, and contemporary legends.