The Science That Finally Explains the Dyatlov Pass Incident

Summary

The video presents a small slab avalanche as a scientifically plausible—but unproven—explanation for the 1959 Dyatlov Pass deaths. It also explains why snow is difficult to model and how a computer-animation technique developed for Disney’s Frozen helped researchers simulate avalanche behavior.

The incident and the avalanche question

Nine experienced Soviet hikers died during an expedition in the Siberian backcountry. Rescuers found five bodies between the group’s tent and a nearby treeline; the remaining four were found months later in a ravine. The hikers had left the tent mostly without shoes or adequate clothing. Some had severe blunt-force injuries, and several details—including missing body parts and radioactive clothing—remained unexplained. The original investigation’s vague conclusion was that an “unknown compelling force” had driven them from the tent.

An avalanche seemed like a straightforward possibility: hikers trained to recognize that danger might flee toward trees, and a slab of snow could cause serious injuries. But investigators doubted the theory because the campsite’s average slope was only about 23 degrees, below the usual rule-of-thumb range for avalanches. They also found little apparent avalanche debris, while footprints near the tent had remained visible.

A Russian reinvestigation in 2019 narrowed its official possibilities to avalanche-related explanations and a hurricane. Nearby weather measurements showed temperatures down to about −30°C and winds of roughly 4–10 m/s, with possible stronger gusts—well below the National Weather Service’s hurricane-force threshold.

Why snow is difficult to understand

Snow can behave like loose grains, a brittle solid, or something in between. Its behavior depends on factors including crystal shape, temperature, humidity, wind, pressure, and how long it has accumulated.

• Wet snow can stick together because water between crystals creates capillary forces.
• Dry snow has more air between grains and can flow in ways similar to sand.
• Sintering is the gradual bonding and restructuring of snow crystals. Over time, pressure and molecular rearrangement make a snowpack more solid and often more brittle.
• Snow accumulates in layers with different properties. Weak layers can form, including depth hoar, a loose, sugar-like layer of ice crystals that is especially vulnerable to sideways shear. If a weak layer fails beneath a cohesive slab, the slab can slide.

Snow scientists can model individual grains or treat snow as a fluid, but neither approach readily captures the full transition from a solid slab to broken, flowing snow. Field measurements are also difficult to collect across all the combinations of weather and snow conditions found in nature.

The modeling breakthrough

For Frozen, Disney’s effects team adapted the Material Point Method (MPM), a technique previously used in scientific simulations. MPM represents material using points that move through a fixed background grid. This lets a simulation track snow as it compresses, cracks, breaks apart, and flows.

The technique was first adapted for visually convincing animation, not to predict real avalanches. Snow physicist Johan Gaume later worked with researchers from UCLA and Disney to refine and test it against physical measurements, making it useful for scientific study. MPM complemented the Discrete Element Method (DEM), which models material as interacting small particles and can simulate cracking, but becomes computationally costly as the number of particles grows.

How researchers evaluated the Dyatlov Pass hypothesis

Gaume and geomechanics researcher Alexander Puzrin used the available evidence to test whether a small avalanche could have occurred:

• They reconstructed the campsite’s terrain using maps, topographical measurements, and photographs.
• They considered the hikers’ reported practice of cutting into the snow to make a flat tent platform.
• They estimated snow conditions from the weather and considered measured wind speeds.
• Their calculations suggested that wind could have transported snow onto the slope above the tent. The cut in the snow may have added stress, while snow’s slow relaxation and accumulating load could have allowed a crack to develop over several hours.
• They then used MPM to simulate the possible slab’s impact. The modeled avalanche could have partly collapsed the tent and caused blunt-force injuries consistent with the autopsy reports, while remaining small enough to leave little obvious debris. Wind or drifting snow might also have obscured its fracture line.

The researchers’ result was that such an avalanche does not violate the laws of physics and could plausibly explain several key clues. It is not definitive proof: the exact snowpack and weather conditions cannot be recreated, and the model does not explain every detail.

Possible sequence of events

Under this hypothesis, the hikers were asleep when wind-driven snow accumulation and the stress from cutting into the slope helped trigger a small slab avalanche. The impact may have damaged the tent and injured some of the group. They may have cut their way out and gone to the treeline, where they tried to build a fire. Later, they might have attempted to return for supplies, shared clothing as some succumbed to hypothermia, and tried to make a snow shelter. The remaining hikers may then have fallen into the ravine.

This sequence is a reconstruction, not an established account.

Radioactive clothing, reports of bright objects in the sky, and other inconsistencies remain unresolved. The video emphasizes that the avalanche explanation is a plausible scientific account, not a final solution to every mystery.

Researchers and sources featured

Researchers and interviewees

• Alexander Puzrin — professor of geomechanics at ETH Zurich
• Johan Gaume — snow physicist and Puzrin’s collaborator
• Dale Mayeda — Head of Effects for Frozen at Disney Animation Studios
• Marlon West — Head of Effects for Frozen at Disney Animation Studios
• Andy Selle — software developer involved in the Material Point Method work
• Alexey Stomakhin — UCLA researcher involved in developing the MPM snow framework

Other sources and institutions

• ETH Zurich
• UCLA
• Disney Animation Studios and the Frozen production
• The New York Times, which contacted Gaume about the avalanche hypothesis
• U.S. National Weather Service wind-speed classification
• Dyatlov Pass case files, photographs, weather-station reports, and autopsy reports
• Hans Christian Andersen’s The Snow Queen, the story that inspired Frozen