Dyatlov Pass 1959: nine hikers, a cut tent and an avalanche verdict

On the evening of 1 February 1959, nine ski hikers dug a platform into the snow on the slope of Kholat Saykhl, in the northern Urals, and pitched their tent. The name means 'Dead Mountain' in the Mansi language. The last photograph of the group, reproduced in the 2021 study[gaume-puzrin-2021], shows them cutting into the slope.

They were led by Igor Dyatlov, and they were experienced. Something happened after midnight. According to Gaume and Puzrin's summary[gaume-puzrin-2021] of the case, the hikers cut the tent open from the inside and left towards a forest more than a kilometre downslope, without proper clothing, in temperatures below minus 25 degrees and strong winds.

Searchers came weeks later. They found the tent collapsed under snow, about 26 days after the event. The bodies were found over the following weeks and months, some in the forest, some on the way back towards the tent. TASS[tass-2020], reporting the official summary, gives the outcome: all but three, Zolotaryov, Dubinina and Thibeaux-Brignolle, died of hypothermia. Those three, and one other, had severe chest or skull injuries.

There is no living witness to that night. What the file has is a cut tent, nine bodies, a few photographs from the hikers' own cameras, and the search party's records.

The first paper is the Soviet criminal case of 1959. It closed with a phrase that has fed theories ever since. According to TASS[tass-2020] and Gaume and Puzrin[gaume-puzrin-2021], the investigation found only that the deaths were caused by 'a compelling natural force'. It did not say which. Transcriptions of the file, including search records and autopsy pages, are published on an independent research site[dyatlovpass-case-files]; the Archive has not checked them against the originals.

For decades the gap was filled with speculation: infrasound, animals, a romantic dispute, nuclear tests, even Yetis, as the 2021 study lists them. Most of these have no primary source behind them.

The state returned to the case twice. Gaume and Puzrin note that the Investigative Committee reopened it in 2015 and in 2019 found an avalanche most probable. In February 2019 CNN[cnn-2019] reported a new inquiry by prosecutors. According to Interfax[interfax-2020], it considered only three natural versions: an avalanche, a snow slab and a hurricane.

On 11 July 2020 Andrei Kuryakov, deputy head of the Prosecutor General's directorate in the Ural Federal District, gave the answer to reporters in Yekaterinburg. An avalanche, after a sharp change in weather, forced the group out. They walked 50 metres, calmly, to a stone ridge. Then, with visibility of about 16 metres, they could not see the tent again. The slope was declared avalanche-prone and the authorities were told. 'The question is closed,' he said.

Inventory: a 1959 case file known through transcriptions, a 2020 official statement known through press agencies, and no written prosecutor's report opened.

The turn in this file came from snow physics, not from a new document.

The avalanche idea was old, and it had four well-known problems. Gaume and Puzrin[gaume-puzrin-2021] list them: searchers saw no clear avalanche debris; the average slope was under 30 degrees; whatever happened came many hours after the tent was pitched; and the chest and skull injuries were not typical of avalanche victims.

Their 2021 model answered each in turn. The slope under the snow was locally steeper than the surface, about 28 degrees. The tent cut removed support from a thin slab. Katabatic winds then blew snow onto the slope above until, after 7.5 to 13.5 hours, a small slab broke loose. Simulations showed that blocks of such a slab, pressing hikers against a tent floor laid on skis, could cause severe but not immediately fatal injuries. In the words of the EPFL release[epfl-2021], quoting Puzrin: if they had not made a cut in the slope, nothing would have happened.

The authors were careful. They call their result a plausibility, say solving the mystery is far beyond the paper, and leave the radioactivity, the hikers' route and the positions of the bodies unexplained.

Then, in the field, the slope answered back. In their 2022 follow-up[puzrin-gaume-2022], Puzrin and Gaume report that winter expeditions found slopes above 30 degrees near the tent site and filmed two fresh slab avalanches less than 3 kilometres away, one already hidden by drifting snow within an hour. That is why, they argue, the 1959 searchers saw nothing three weeks later.

So the grade here is Recorded, and the finding Explained: an avalanche, now with an official verdict and a published mechanism. Not every detail, but the core.

What is still open about Dyatlov Pass is the part the avalanche does not reach.

First, the walk. Why did nine experienced hikers go more than a kilometre downslope, many barely dressed, instead of digging out the tent? The prosecutor's answer, via Interfax[interfax-2020], is that they went 50 metres to safety and then could not see the tent. That is an explanation, not a demonstration. The 2021 study[gaume-puzrin-2021] explicitly does not address it.

Second, the injuries. Gaume and Puzrin show that a slab could cause them at the tent. They also say it is possible the chest injuries happened later, in the steep ravine where four bodies were found. The autopsy pages have not been opened for this file.

Third, the radioactivity and the other strange details: traces on some clothes, missing eyes and a missing tongue. These are reported in the 2021 paper from earlier books. The Archive has not opened the laboratory reports and does not stamp any theory built on them.

Fourth, the families. The relatives' lawyer, quoted by Kommersant[kommersant-2020], rejected the 2020 finding and pointed to a man-made disaster. No source in this file supports a weapons test or military cover-up, but the families' disagreement is part of the record.

Fifth, the papers themselves. No written report of the 2020 inquiry has been found, and the 1959 file is read here only through an independent transcription site[dyatlovpass-case-files].

The honest position: Recorded, nine deaths and a cut tent in 1959. Explained, officially and physically, as an avalanche followed by exposure. Open, the route, some injuries and the radioactivity.

• Why walk away from the tent?
• Where were the worst injuries caused?
• What do the original radiology reports say?

The folder stays open and the file stays a draft for the editor.