Dyatlov Pass incident

Dyatlov planned to climb the Otorten and Ojka-Czakur peaks in the Northern Urals.

An excerpt from the article 39 facts about Dyatlov Pass incident

Otorten was a gentle peak of Mount Kholat Syakhl but had never been climbed in winter conditions. The difficulty was not so much to climb the gentle peak (between 1182 and 1234 meters above sea level), but to cross the Ural taiga in harsh winter conditions. The temperature at night often dropped below 30 degrees Celsius, and blizzards, snowdrifts, and strong winds were a constant feature of the landscape. In addition, the Ural Mountains at the time were in an area of ongoing military operations, making maps of the terrain secretive (the last available map was dated 1941). The group could only rely on their intuition and a map identifying checkpoints to the nearest 10 kilometers or so.