Flathead Avalanche Center Reflects on Season of ‘Remarkably Reactive’ Snowpack

Months after the Flathead Avalanche Center (FAC) issued its final daily forecast for the season, officials released the 2020-2021 annual report in July that reflected a unique winter with an unprecedented volume of near-misses and accidents, including a fatality, in the Swan, Whitefish and Flathead mountain ranges.

Last season, the FAC saw a spike in near-misses, or unintentionally triggered slides where no one was caught; incidents, which is anytime a rider comes into contact with moving avalanche debris; and accidents, where a person is partially or fully buried, injured or killed.

Of the 18 total near-misses and accidents, 13 occurred in February thanks to a “remarkably reactive” snowpack that contributed to a rate of one event every other day.

“That spike in accidents in February is not something we see regularly at all,” FAC Director Blase Reardon said. “Every other day is the kind of rate of incidents that you’d see in the Wasatches or more urban areas. It’s not typical for here and it’s an unusual confluence of conditions.”

Since the other winter months did not see an unusual volume of accidents, Reardon says a particularly reactive and widespread persistent weak layer that formed in January is likely the culprit, combined with recreationists’ inadequate preparedness for unusual conditions.

In mid-January, a significant storm brought two or more inches of snow-water equivalent (SWE), followed by a rain event and cold front, leaving a “two-month legacy” and producing a widespread natural avalanche cycle that recorded more than 240 natural avalanches, according to the report.

The crust created an unsupportable bed surface that would create a “lethal and lingering avalanche problem.” The next storm was followed by a 10-day dry spell with cold temperatures, creating an additional weak layer of surface hoar and facets in mid to high elevations.

The FAC started receiving a slew of avalanche reports at the end of January, and an avalanche on Feb. 6 in the Swan Range killed a snowmobiler. From Feb. 12 to Feb. 20, seven separate incidents, near-misses and accidents occurred in the Flathead, Whitefish and Swan ranges. Many of the slides were remotely triggered, meaning the avalanche fractured a distance away from where the person triggered it.

“Travel conditions remained good and it was susceptible to human triggers,” Reardon said. “People didn’t have a lot of signs of instability … I think the combination of this really reactive instability combined with good travel conditions, people got themselves into trouble.”

But Reardon also suspects the pandemic-driven behaviors contributed to the spike. The region reflects a nationwide trend of avalanche accidents that the country hasn’t seen in decades.

“I do wonder if it’s more than a coincidence that we had the highest number of fatalities in a month in half a century or more and that month coincided with the start to the end of a pandemic,” Reardon said. “People were starting to get vaccinated and they were cooped up.”

While there’s no data to support this theory, Reardon says he noticed more people in the backcountry, particularly more hybrid riding where skiers accessed terrain with snowmobiles. Anecdotally, Reardon observed there were roughly three-dozen sleds parked at the Olney trailhead on any given weekend.

But the spike in users and accidents also meant that more people submitted field observations this season, which helped forecasters identify hazards across the region.

“We had more observations last year than we ever had,” Reardon said. “We grew 5% over the year before and all that growth came from the public … Along with more use, we saw a lot more engagement.”

In the winter of 2015-2016, the FAC saw fewer than 200 observations, while there were more than 500 observations in the winter of 2020-2021.

“Those observations are the backbone for our products,” Reardon said. “We simply cannot cover everywhere and see all the different micro-climates and those observations are absolutely essential.”

New weather stations are also contributing to FAC’s forecasting abilities. Officials installed a wind sensor on Mount Aeneas in the Swan Range in 2019 and the Tunnel Creek weather station along the Middle Fork corridor in the Flathead Range last year, both filling weather data voids in popular backcountry zones. This spring, Big Mountain’s weather station also received some upgrades with safety improvements, including a heated wind sensor to prevent rime buildup.

Forecasters hope to add another weather station to the central Whitefish Range in the future, an area that has seen more traffic in recent years.

While the pandemic brought hurdles to the educational aspect of FAC, it also opened virtual opportunities to educate a widespread audience.

In collaboration with Friends of Flathead Avalanche Center (FOFAC), the normal lineup of avalanche courses was offered throughout the season, including the Northern Rockies Snow and Avalanche Workshop (NRSAW), as well as Avalanche Level 1, Level 2 and a motorized Level 1 course. Classes were a combination of virtual and in-person style learning.

Educators saw more engagement from motorized users this season, and to address the demand, FOFAC will offer a motorized Level 2 course next season along with additional motorized Level 1 courses.

New this year, FOFAC launched a mentorship pilot program designed for people who recently took the Avalanche Level 1 to help sharpen their new skills.

The program included six mentors paired with six mentees who are given a topic to practice while in the backcountry. Pairs work together to go over their route plan, assess conditions and communicate with FOFAC coordinators using a Garmin inReach device.

“It’s a way for more peer-on-peer learning and taking that Level 1 to the next level,” FOFAC Director of Operations Emily Struss said. “It builds that community energy and provides more opportunity for folks to learn.”

For the 2021-2022 season, educators will offer the mentorship program, as well as more in-person material while still using a virtual model. They will also bring back FOFAC’s youth program.

To donate to the FAC via the Whitefish Community Foundation’s Great Fish Community Challenge, visit whitefishcommunityfoundation.org/great-fish.

For more information, visit www.flatheadavalanche.org.