The Dyatlov Pass incident refers to an event that resulted in the deaths of nine ski hikers in the northern Ural mountains. The incident happened on the night of February 2, 1959 on the east shoulder of the mountain Kholat Syakhl (Холат Сяхл) (a Mansi name, meaning Mountain of the Dead). The mountain pass where the incident occurred has been named Dyatlov Pass (Перевал Дятлова) after the group's leader, Igor Dyatlov (Игорь Дятлов).
The lack of eye witnesses to the circumstances of the accident, and subsequent journalistic investigations of the hikers' deaths have inspired much speculation. Investigations of the deaths suggest that the hikers tore open their tent from within, departing barefoot in heavy snow; while the corpses show no signs of struggle, two victims had fractured skulls, two had broken ribs, and one was missing her tongue.  According to sources, the victims' clothing contained high levels of radiation — though this was likely added at a later date, since no reference is made to it in contemporary documentation and only in later documents. Soviet investigators determined only that "a compelling unknown force" had caused the deaths. Entrance to the area after the incident was barred for three years. The chronology of the accident remains unclear due to the lack of survivors to the accident.