>https://en.wikipedia.org/wiki/Dyatlov_Pass_incident
>The Dyatlov Pass incident (Russian: Гибeль тypгpyппы Дятлoвa, romanized: Gibel turgruppy Dyatlova, lit.'Death of the Dyatlov Hiking Group') was an event in which nine Soviet ski hikers died in the northern part of the Ural Mountains ridge in the Russian SFSR of the Soviet Union on 1 or 2 February 1959 under undetermined circumstances. The experienced trekking group from the Ural Polytechnical Institute, led by Igor Dyatlov [ru], went on a hike of the highest difficulty level at that time, and had established a camp on the eastern slopes of Kholat Syakhl mountain. Overnight, something caused them to cut their way out of their tent by knives and flee the campsite while inadequately dressed for the heavy snowfall, strong winds and highly subzero temperatures as low as −50 °F (−46 °C).