Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Fresh snow and wind may continue forming thin slabs in areas open to and sheltered from the wind. These slabs will increase in thickness and become more widespread as you gain elevation and in areas favored by snowfall. Overnight rain and today's warming temperatures may lead to wet avalanche concerns. Rollerballs and snow falling from trees direct you to seek out lower-angle slopes.

Forecasted snowfall overnight may increase the avalanche danger, especially in the Swan Range, where the most new snow is expected. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Favored locations have received 4-8+ inches of new snow over the past two days, with additional accumulations through tonight. On Friday, north and east winds built thin slabs on atypical aspects. This morning, winds shift back to the west and become strong enough to drift snow and form slabs on the other side of the compass. Look for these features near exposed ridgelines and mid-slope gullies. As you climb in elevation, these slabs will be thicker and more widespread.

    In locations sheltered from the wind, you may encounter thin slabs in the newly fallen snow. These slabs will be more widespread and dangerous in areas with the most snow accumulation. 

    Both slab flavors will feel dense and may support your weight and your machine's weight. Cornices, dunes, and rippled snow are clues that the wind has been at work. Cracking around your feet or machine indicates that you have found a sensitive slab directing you to seek out less steep terrain. 

    (3/23/2024)

    Dunes and drifts on the lee side of small trees and rock outcroppings are evidence of the winds at work.  In this image, the wind blew from left to right.

    Photo: Mark Dundas

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Overnight wet snow, rain, and afternoon warming keep wet avalanches on the problem list. This morning, expect a rain-saturated surface below last night's snow line. Above that elevation, you will likely trigger rollerballs and wet slides in the new snow on steep slopes. These should be relatively small and harmless, except in large continuous terrain and gulleys, where escape may be difficult. 

    Snow falling from tree branches or shedding off rock outcroppings indicates warming, while natural and triggered rollerballs are evidence the surface snow is losing strength. These are all signs to seek out lower-angle terrain free of overhead hazards. Limit your time spent above terrain traps, where debris can pile up and push you into places you don't want to go.

    (4/5/2024)

    Today every aspect had fields of rollerballs. We suspect that increased wet loose activity occurred in the afternoon. We didn't stay around to watch it happen. 

    Photo: Sarah Williams

Avalanche Discussion

Beneficial moisture returned to the Flathead overnight on Thursday and Friday with 0.5 to 1 inch of precipitation and 4-8 inches of settled dense snow at mid-elevation stations. With cooler temperatures at upper elevations, we expect these locations to have received several additional inches. Gusty north and east winds subsided Friday, and the winds will shift back to the southwest and increase through today.

The snowline associated with the recent precipitation remained well above the valley floor, resulting in a rain-saturated snowpack below roughly 5,500 to 6,000 feet. Wet snow avalanche concerns will be present in these areas this morning. Mild afternoon temperatures may moisten the recent snow above, with the possibility of wet snow avalanches on steep slopes climbing in elevation as the day progresses. 

Observations have been limited lately. Yesterday, Sarah and a volunteer visited the terrain east of the WMR ski area. They found thin slabs, drifts, and dunes in unusual locations. The 3 inches of new snow warmed quickly, and rollerballs became common with almost every turn.  

It’s been over two weeks since the last reported avalanche failing on weak layers buried 2-4+ feet deep. With another round of warming behind us, we’ve elected to drop the Persistent Slab problem, which we first listed in mid-February. You can continue reducing your risk by choosing slopes with a stout crust in the top two feet or avoiding rocky terrain where the snowpack has variable depth.  

It's hard to believe, but FAC's last daily forecast will be Monday, April 8, 2024. After that, we will continue to issue conditions updates on Tuesdays and Fridays until May 3 or as conditions dictate. 

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