Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Wed
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired last year. You’re viewing past conditions, not the current bulletin.

Highlights

You may still find dry snow and soft riding on high, shaded northerly slopes  - the same terrain where you might be able to trigger large avalanches that break on weak layers buried 2 to 3 feet deep. If the surface snow isn't a supportable crust, carefully evaluate the snowpack structure and potential consequences before committing to steep terrain. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–2.5

    The Atmospheric River and extended warming temperatures have put the snowpack through the wringer, shaking out many of the weak layers through natural activity. Avalanches are unlikely where a supportable melt-freeze crust exists on the snow surface. However, in steep terrain undisturbed by recent slides, the right trigger in the wrong spot may still cause large avalanches that release on weak layers buried 2 to 3 feet deep. Isolated whumpfing collapses and propagating results are still being reported. 

    You may trend towards the shaded, high elevation slopes holding both the best snow and most sensitive persistent slab structures. Dig down to look for layers of buried surface hoar and/or facets near crusts before committing to steep terrain. If column tests produce sudden collapses or propagation, step back to lower-angled, simpler terrain. 

    (3/2/2025) Wide crowns on the east face of Mount Grant. Triggering avalanches like these remains possible today. Photo: Paul Fotter

Avalanche Discussion

Well, that was an active 10 days in the mountains. Two widespread natural avalanche cycles, the first resulting from rain and dense snow dropped by an Atmospheric River. Snow lines during this event climbed to over 6000 feet. The second cycle was prompted by strong solar radiation and several days with air temperatures above freezing.  Most of the slides in both cycles were large to very large (D2-3); there wasn't enough debris volume for avalanches to be much bigger or more destructive. Most failures occured on weak facets or buried surface hoar left by the dry January. In the second cycle, wet snow avalanches occurred on solar aspects at upper elevations. 

Cloudy skies and cooler temperatures have paused the mayhem. After 24-40 hours of sub-freezing air temperatures and mostly cloudy skies, the wet snow at the snow surface has refrozen. That cap makes triggering slabs on the January drought layers unlikely. The exceptions are slopes where the near-surface snow is mostly dry, or where any crust at the surface doesn't support your weight. That'll mostly be shaded slopes above about 6000 feet. We've nonetheless listed the problem on all aspects. After widespread slab avalanches on southerly slopes, its hard to discount the possibility that there may be isolated slopes on sunnier aspects where a rider could still trigger a slab on the facets that developed during January. The warm temperatures are helping these facets and buried surface hoar to settle and round, albeit slowly. 

Observations indicate that the snowpack at low elevations is isothermal and unsupportable. On isolated steep slopes, the snowpack may not have fully drained, and a person may still be able to get enough wet snow moving to be dangerous. I'd remain leery of steep gully walls and other terrain traps.

The hazard posed by open glide cracks has also diminished as clouds and cooler temperatures have limited the amount of meltwater percolating to the base of the snowpack. Gravity is still tugging slabs below open cracks downhill, so don't dawdle below any brown frowns. 

Both of the above hazards are likely to return later this week as a ridge builds on Wednesday, bringing strong solar radiation and more above-normal temperatures. 

Regions covered