Research suggests avalanche activity is being altered by climate change
Mar 31, 2025, 5:52 PM
Wasatch Backcountry Rescue skiers search the remnants of an avalanche at Big Cottonwood Canyon in Cottonwood Heights on March. 6, 2023. (Ryan Sun/Deseret News)
(Ryan Sun/Deseret News)
SALT LAKE CITY — As the climate changes, some research suggests it is impacting avalanche activity. Experts believe several factors are contributing.
First, global temperatures are rising. According to the Environmental Protection Agency, increased temperatures have been accompanied by changes in weather patterns. For example, some areas have experienced heat waves, heavier-than-normal precipitation, and volatile, unpredictable storms.
These events have contributed to the volume and density of snowpack. Several factors influence avalanche activity, including temperature, precipitation, wind and slope angle.
Per the Natural History Museum of Utah, Utah winters are an average of 37 days shorter than they were in the 1930s. Additionally, warmer temperatures cause more precipitation to fall as rain, as opposed to snow, therefore lowering snowpack totals.
How could warming temperatures impact avalanche activity?
A study published by the National Library of Medicine explained that warmer temperatures could lead to less snow cover at lower elevations. At higher elevations, however, avalanches could become more intense.
Avalanche activity largely depends on interactions between existing snowpack, new precipitation, and temperatures.
Rescuers start the excavation process after an avalanche killed a man who was split-boarding alone in Big Cottonwood Canyon. (Utah Avalanche Center)
Snowpack stability and warm temperatures
A stable snowpack relies on consistent snowfall and moderate, steady temperatures. Per Scientific American, continued temperature fluctuations cause problems with bonding between snowpack layers.
In other words, consistent weather leads to better snowpack stability. Although avalanche danger is never absent, stable snow leads to safer conditions.
Temperature fluctuations play a role in the dreaded persistent weak layer, which has been a continued problem in Utah’s avalanche conditions this winter. Persistent weak layers are those that don’t bond to the snow above or below them, complicating avalanche risk.
Additionally, warmer temperatures can lead to a wetter snowpack. When rain —which is warmer than snow— falls onto snow-covered slopes, it can break the bonds between snow grains far below the surface.
Sierra Avalanche Center explained that rain leads to rain crusts within the snow. They are often surrounded by weak layers of snow.
Parts of a tree poke out of the snowbank after an avalanche at Alta on April 9, 2023. (Ryan Sun/Deseret News)
Avalanche activity and backcountry users
According to the State of Utah’s Hazard Mitigation website, avalanches accounted for 70% of severe weather-related deaths between 1996 and 2022.
The number of future backcountry users could impact the rate of human-triggered avalanches, therefore potentially increasing avalanche fatalities, per the NIH-published study. Conversely, if backcountry visits declined, the rate of human-triggered avalanches and fatalities might decrease.
Regardless, the severity of injuries sustained in avalanche accidents could increase as climate change continues. The study said that thinner snow cover further exposes victims to rough terrain, such as rocks and logs that sit beneath the snowpack.
Additionally, higher-density snow could result in increased suffocation-related avalanche deaths.
Per the Colorado State University Climate Center, snow density refers to the relationship between snow’s weight and water content. It can vary based on the space between crystals, their size, or their shape, and contributes to avalanche danger, the strength of snow and how easy it will be to remove.
Wet, heavy snow is considered more dense, whereas Utah’s famous light, fluffy powder has a lower density.
Per the University of British Columbia, warmer temperatures and faster winds cause fresh snow to have a higher density.
Avalanche deaths
During avalanche accidents, Frontiers associated higher snow density with rapid oxygen depletion. Since warming temperatures lead to wetter, higher-density snow, they could lead to decreased avalanche survival rates.
Currently, according to the Utah Avalanche Center, 93% of buried victims can be rescued if they are dug out within 15 minutes of being buried. As time goes on, the number dramatically decreases. After 45 minutes, for example, the percentage decreases to between 20 and 30%.
UAC’s website explains that said buried victims often die as the carbon dioxide emitted from their exhalations builds up in the snow surrounding them.
Read about current Utah avalanche activity: Forecasters advise adaptability amid considerably dangerous avalanche conditions
