BOZEMAN – Southwest Montana’s snowpack has been relatively stable in the last week or two with the avalanche danger holding in the low category for most ranges. The Cooke City area has the highest avalanche danger which is rated at moderate.
This past Sunday, a snowmobiler was killed in a rider-triggered slide in the Lionhead region west of West Yellowstone. According to the Gallatin National Forest Avalanche Center, that slide was a relatively small avalanche that was between 4”-11” deep, 75 feet wide, and only ran about 100 yards. The rider was caught and pinned against a tree in the slide with his head buried. The slab of snow was on top of a persistent weak layer of snow that was released on a 45° slope.
When MTN News spoke with Dave Zinn from the Gallatin National Forest Avalanche Center, he emphasized the need to be vigilant even when avalanche danger is low. Speaking about the incident, Zinn explained the inherent risks involved with backcountry recreation in southwest Montana. “Low danger does not mean no danger,” Zinn said. “The snowpack in the mountains is always changing” Zinn said. “The wind has been blowing in the northern ranges and that has been moving a lot of snow”.
Zinn explained that the wind and temperature changes keep the forecasters on their toes when assessing the risk for avalanches. “Even right now with low danger [of avalanches] we know that there are isolated areas where weak layers persist” Zinn explained. “Those dangers relate to two things” Zinn said. “Wind-loaded slopes are small but stabilizing and the second issue is this weak layer that is buried between 6” and 18” of snow”.
In Sunday’s event the riders were properly trained and had all the equipment, but the avalanche wasn’t seen right away. The folks at the Gallatin National Forest Avalanche Center continue to emphasize the need for safety classes, many of which are offered at low or no cost. You can get a full list of classes offered on the GNFAC website.
Sunday marks the third avalanche related death this season in southwest Montana. This comes on the footsteps of the 2020-2021 season, which was a record year for deaths related to avalanches in the the United States with 37 fatalities. This year there have been 9 deaths due to slides, three of which were in Montana. Other deaths in the United States include 3 in Colorado, 2 in Idaho, and 1 in Washington, as well as the 3 killed in Montana.
While the snowpack is still fairly stable, keep in mind that there are several chances of snow in the mountains of southwest Montana through the weekend, with another good chance for snow moving in early next week.