In February 1959 a group of hikers disappeared in the remote Ural Mountains of Western Siberia. A search party found their tent weeks later, abandoned along with all of their equipment. Frozen bodies were found 1,500 meters away, mysteriously underdressed for the weather conditions: most weren’t wearing shoes or gloves, and some were just in their sleeping clothes. Even stranger, three of the hikers had suffered major internal trauma — broken ribs and a fractured skull — and two were wearing clothes contaminated with radioactive substances. Nonetheless, the lead Soviet investigator closed the criminal case into the hikers’ deaths, concluding that an “overwhelming force” is what drove them from the tent. Theories ranging from rare weather events to conspiracy to UFOs have developed ever since, to explain what is now called the Dyatlov Pass incident. But two plausible theories, each involving an “overwhelming force” may finally explain what happened that night.