Mountain goats are iconic in the mountainous regions of the western United States – often seen navigating steep, rugged terrains with ease. These difficult terrains offer mountain goats protection from predators like wolves, but also expose them to the danger of avalanches.  

Alaska CASC-supported researchers examined how often coastal Alaskan avalanches cause mountain goat deaths in a new study published in the journal Communication Biology. Using 17 years of data that tracked the movements of over 400 satellite-tagged mountain goats across southeastern Alaska, the researchers were able to estimate that avalanches account for an average of 8% of mountain goat deaths annually. However, in one year, this percentage was as high as 22%, posing a significant threat to small, isolated populations. Unlike predation or malnutrition, which select for older or weaker animals, avalanches cause death more randomly, also killing healthy, reproducing individuals. The deaths occurred throughout nine months of the year, with spikes during snowpack development (October-November) and melting (April-May). Despite these risks, avalanches can also provide opportunities to mountain goats. They promote early spring plant growth in avalanche chutes with lower snow cover and can help expose vegetation for winter foraging.  

Changes to climate, weather, and snow patterns are expected to shift habitat and avalanche risk for mountain goats and other alpine species. This study, supported by the Alaska CASC, offers insights to managers assessing avalanche-related risks to mountain goat populations in southeastern Alaska. 

This study was funded by the Alaska CASC Project titled “Evaluating How Snow Avalanches Impact Mountain Goat Populations in Southeast Alaska.”