Nine members of Igor Dyatlov's ski group died on the east slope of Kholat Syakhl, above the pass that now carries his name, on the night of 1 to 2 February 1959. This report tests the explanations of their deaths against the 1959 case file.
Primary evidenceThe 1959 criminal case «О гибели туристов в районе горы Отортен» ("on the death of the hikers near Mount Otorten"), volume 1, 392 sheets: scene protocols, interrogations, the search's radio messages, nine autopsy acts, the radiological expertise and the resolution of 28 May 1959, read in Russian on the scans and transcriptions at dyatlovpass.com and cited by sheet («л.д.», the Russian abbreviation for a numbered sheet of a case file).Tested againstThe 2021 slab-avalanche model of the snow scientist Johan Gaume and the engineer Alexander Puzrin, and their 2022 follow-up; the Russian prosecutors' review of 2019–20; the avalanche version of the engineer Evgeny Buyanov (2011); the fall-wind theory of Richard Holmgren (2019); the infrasound theory of Donnie Eichar (2013); the KGB theory of Alexei Rakitin (2013); the rocket, Mansi and minor theories; and the field critics of the avalanche, the aviation engineer Vladimir Borzenkov and the 1959 searchers Vladislav Karelin and Sergey Sogrin.Method459 facts extracted from the file with sheet numbers; independent slope, darkness, weather and walking-time computation; a from-scratch reimplementation of the slab release and impact models; 28 facts scored against nine explanations. Code and data are saved with the report.