By working together, Alaska CASC researchers confirm avalanches are a major contributor to mountain goat fatalities

A study by Alaska Climate Adaptation Science Center scientists revealed that mountain goats in Southeast Alaska may be at higher risk for mortality as they are pushed deeper into avalanche terrain.

The study found that 36% of coastal Alaska mountain goat deaths are a result of avalanches – a finding Alaska CASC researcher and mountain goat expert Kevin White had long suspected and was able to confirm with the help of avalanche researchers.

White said avalanche mortality had been documented anecdotally among mountain goat populations in previous studies, but never formally quantified. He and other biologists and outdoorsmen have even seen and reported goat carcasses in the runout zones of avalanches. It led White to wonder about the overall severity of impacts.

Mountain goats spend their lives high in the mountains. These mountains provide the habitat needed for their daily life while also providing safety as mountain goats are able to flee to high cliffs that are inaccessible to predators. But that same safety mechanism can also increase exposure to avalanches with often fatal outcomes for both the mountain goats and any other animals in the hazard zone.

White, a wildlife ecologist and researcher with the University of Alaska Southeast based in Haines and a self-described “mountain goatologist,” has collected data on mountain goats for the last 17 years in the Coast Mountains that run throughout Southeast Alaska. During that time he collected location, tracking and demographic data from 421 different mountain goats in the region. With each goat tagged with a GPS collar for about three years, that means White collected the equivalent data of 1,218 mountain goat years.

That extensive data piqued the interest of Eran Hood, a professor of environmental science at the University of Alaska Southeast with an interest in snow science. Hood, who has known White for decades, invited him to speak on mountain goat research for a 2019 seminar class on the impacts of avalanches. It was during that class that Hood thought about how the data could be put to use understanding a different way that avalanches impact ecosystems, one with potentially significant implications for wildlife populations.

Hood was familiar with snowfall impacts on wildlife through previous experience and collaborations – from how increased snowpack can lead to increased predation or animals lacking access to food. But looking at avalanches and mortality on mountain goats “is really a different way that snow could influence the population that we felt like hadn’t been looked at before,” he said.

“I know over the years, (White) would say, ‘oh, I found a mountain goat or a moose that was killed by an avalanche,’ and I would sort of hear about it over time,” Hood said. “It seemed to happen fairly often, and then when we kind of put all of the data together, you could see the magnitude of just the role that avalanches could play.”

Using Alaska CASC funding, the researchers teamed up with Alaska CASC scientist Gabriel Wolken. Wolken was one of the scientists who developed avalanche susceptibility maps for Southeast Alaska, and compared the mountain goat movements with the avalanche terrain.

Overlaying the goats’ location data on mapped avalanche release areas and runout zones allowed scientists to assess how their exposure varied among individual animals and over time.

What the scientists found was that the number of mountain goat deaths exceeded 60% for those living in the most avalanche-prone areas in Southeast Alaska. Overall avalanches killed about 8% of the mountain goat population annually, rising to 22% in severe winters.

For a long-lived species that reproduces slowly – most goats live to be between 7-8 years old and birth one kid a year – those loss levels make avalanches a major influence on population dynamics. With increasing recognition about the risk of avalanches, Hood and White realized that it’s important that people know how to prevent mountain goats from inadvertently running into avalanche terrain.

White said that mountain goats are particularly sensitive to human disturbance. Humans recreating in the mountains – whether for hunting, hiking, backcountry skiing or snowmachining – should give mountain goats space. Not only will this prevent mountain goats from being displaced into risky avalanche terrain, but knowledge about how to move safely through avalanche terrain will keep humans safe as well – perhaps even from an avalanche triggered by a fleeing goat.

“We realized (from the study) how much danger mountain goats are in from avalanches just in general,” White said. “This is one thing that humans can do to help mitigate that.”

The research could lead to further developments including understanding how avalanche risk impacts other Alaska ungulate species including Dall sheep and mountain caribou. It’s also valuable to better understand how avalanches influence mountain ecosystems in beneficial ways – in some cases accelerating spring green-up in snow-free slide zones that provide feeding opportunities for goats and other animals or, more broadly, increasing habitat and biodiversity. Their research has also described how wolverines scavenge the carcasses of the mountain goats caught in the avalanches, providing a surprising source of hard-to-find winter calories.

“An interesting further dimension of our work has been trying to understand more about the benefits of avalanches,” White said. “It’s not just mountain goats that are affected but wildlife communities and alpine ecosystems in general.”

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To learn more, please download this informational page on how to protect mountain goats from avalanches. A social media kit is also available for those interested in sharing information about mountain goats in avalanche terrain.

For more information please contact Alaska CASC Science Communication Lead Suzanna Caldwell at secaldwell@alaska.edu.