THE LOCAL NEWS OF THE MADISON VALLEY, RUBY VALLEY AND SURROUNDING AREAS

This map shows relative avalanche danger for Madison and Gallatin counties. With extreme terrain, shifting winds and adventurous winter recreationists, southwest Montana is a hotbed of human-triggered avalanches. (avalanche.org)

Far from over

With many winter days left, avalanches are a pressing danger

MADISON COUNTY—In 2018, four fatal avalanches were reported to the Gallatin National Forest Avalanche Center (GNFAC). Overseen by the U.S. Forest Service, the GNFAC covers the Bridger, Madison and Gallatin mountain ranges—from Bozeman to West Yellowstone, Big Sky to Island Park, Idaho. 

The first three of those fatal avalanches occurred in January: a snowmobiler died in a self-triggered avalanche on Sage Peak south of Ennis on January 2; another snowmobiler died in a similar incident in the Centennial Range of Island Park on January 10; and a snow biker triggered an avalanche less than two weeks later on January 20 in the same area.

Later in 2018, a skier entered the backcountry just south of Bridger Bowl ski area near Bozeman and triggered a fourth avalanche on April 15, which was also deadly. 

And those incidents were just four of over two dozen “avalanche incidents” that the GNFAC reported in 2018. Nearly half of those occurred in the Madison mountain range. 

Even with the federal government shut down for over two weeks, the GNFAC provides such important public safety information that they’re classified in the same category as law enforcement, working through the shuttering of national and state parks and other Forest Service stations.

“There’s avalanches that get reported, but the number we’re really interested in is incidents when someone got surprised,” says Doug Chabot, GNFAC director. “In a busy year, we can have 80 incidents. It’s feeling a bit below average this year; in general, the snow hasn’t been wildly unstable.”

Chabot and his team spend much of their time on snowmobiles and skis themselves, in the field determining the strength of the snow already on the ground, then factoring in the potential impacts of impending weather activity to determine the likelihood of avalanches in the places recreators are most likely to frequent. 

“We go where the people go, and let them know what we’re thinking,” Chabot says. “What can that snowpack handle, and what kind of structure does it have? Then we can let people know what the danger is like.”

Once they’ve determined that danger, the staff at the GNFAC update a daily avalanche forecast on their hotline, which recreators can call to hear the latest information. The forecast includes everything from recent snowfall and current temperature and windspeed to the stability of snow around the three mountain ranges and stress factors such as new snow, observed natural avalanches and a rating from mild to extreme avalanche danger.

Chabot himself is aptly prepared for his job. A former professional ski patroller at Bozeman’s Bridger Bowl and a trained mountain guide and climber, he’s worked for the GNFAC as an avalanche specialist for nearly 24 years. 

The main concern for the GNFAC is human-triggered avalanches, he says. While its avalanche activity database does include reports of natural events, they focus on providing skiers, snowmobilers and hikers with the information, warnings and education they need to avoid getting swept away—and possibly killed.

“The reason we’re here is because people are out there recreating and they get in trouble,” he says. “Around southwest Montana we have that convergence of terrain, weather and snowpack that adds to that danger. When we see natural avalanches, we know people will trigger them too.”

For instance, the majority of the Beaverhead-Deerlodge National Forest has a notoriously shallow and weak snowpack. Without knowing what could be under those layers of snow or whether there’s a particularly weak layer, recreators are unable to tell whether it will remain under their feet or slide down a steep mountain face, taking them along with it.

 

Rule No. 1: Be prepared

The Beaverhead-Deerlodge National Forest (BDNF) advises recreators to always ensure that everyone in their backcountry party carries an avalanche transceiver, shovel and probe on their person. In an avalanche situation, the transceiver can help locate someone trapped underneath snow, and the probe can help to determine the depth and stability of snow.

It’s also vital to know the immediate and extended forecast for the area you’ll be skiing or snowmobiling in. That also includes the recent past: recent snowfall can hide cracks in the snow surface or other telltale signs of avalanche danger, in addition to adding weight to an already heavily burdened snowpack.

The BDNF also advises that hikers, skiers and snowmobilers be on the watch for “whumping,” a sign of unstable snow characterized by cracking or collapsing of snow patches. In areas where cracks or collapsed snow is visible, it’s wiser to seek out lower-grade terrain or a more established trail. 

 

Rule No 2: Study up

Chabot says the number one way to prepare for setting out into avalanche terrain is to take a class before you go. Avalanche classes are widely accessible through various retailers, recreation organizations and bodies like the GNFAC, which offers classes nearly daily ranging from snow science to skills clinics, field trips and rescue classes. 

“You’ll learn about why they form, where they form and how to avoid getting caught in them,” Chabot says. “If you’re willing to accept that risk and play in avalanche terrain, you have to up your game and get more education to be able to assess the snow.”

Assessing snow begins with knowing the necessary ingredients to trigger an avalanche, he says. That begins with a steep slope—30 degrees or steeper—and, obviously, snow. Add to that snow a weak layer, facilitated by a brief warm spell to partially melt some of the snowpack or unstable terrain weakening the snow, and you have a situation ripe for an avalanche if the fourth ingredient—a trigger, like a skier, an animal or even wind moving snow from one area of a mountain to another—gets added to the mix.

“All snow isn’t equal,” he says. “It changes when it hits the ground. Sometimes the snow that’s on the ground might be strong or weak in its ability to hold a snowstorm on top of it.”

Gauging that can be tricky just by looking, but with the proper tools and preparation, the likelihood is far greater that recreationists will be able to identify the safest places to enjoy southwest Montana’s winter activities. Charbot notes that this winter has been slower than average in terms of human-triggered avalanche activity, and while there is still a lot of winter left in 2019, he’d like to keep it that way. 

 

To learn more about the GNFAC or to find avalanche resources, visit www.mtavalanche.com or www.avalanche.org, which maps the highest-risk areas for avalanche potential including those that are under avalanche advisories. To hear the GNFAC’s daily avalanche forecast, call 406-587-6981.

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