In February 1959, nine experienced hikers died during a winter expedition in the northern Ural Mountains of the Soviet Union. When search teams eventually found their camp, the tent had apparently been cut open from inside, and the hikers had fled into extreme cold without properly dressing for the conditions.

The investigation uncovered bodies scattered between the forest and the abandoned campsite, with some victims dying from hypothermia and others suffering severe traumatic injuries. Decades of theories followed, from military experiments to unexplained phenomena, but modern snow science has shown that a delayed slab avalanche could plausibly explain many of the strangest details.

Did an unusual avalanche trigger a chain of fatal decisions, or does part of what happened on that frozen mountainside remain beyond reconstruction?