Lawinenlagebericht

Flathead Range & Glacier NP

Flathead Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

Dangerous avalanche conditions exist due to yesterday’s (Tuesday) snowfall and wind. Avalanches may involve new and drifted snow or step down to buried weak layers, producing large, unsurvivable slides two to three feet deep. Slopes that face south or are at a gentle angle will offer the greatest level of safety today, while still providing access to recent, abundant snow.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    Recent snow and wind have increased the slab thickness above a preserved weak layer at mid- and upper elevations. Slabs range from two to three feet deep and are likely thicker in alpine areas. Resulting avalanches will move fast, travel far, and entrain copious amounts of snow.

    Whumphing sounds are a clear sign that the area you’re in or on has a hard snow (slab) over soft snow (weak layer)structure. Places where you receive this audible clue likely harbor a thinner slab, allowing you to be closer to the weak layer. Stay far back from rollovers of ridgelines and steep parts of a slope. Triggering large avalanches remotely from above, below, or to the side of a slope is possible, as evident by events from the last several days. Collapses could propagate long distances and connect across terrain features like ridges.

    Gentle slopes, particularly those that face the sun, provide wonderful skiing and riding opportunities right now.

    (2/17/2026)

    The troubling surface hoar layer is now buried 75 cm below the surface. It propagated with with hard force (ECTP 22). The block cash-registered into our laps with startling energy. An ECT on a nearby slope on 2/10 did not propagate. A thin ice lens between the BSH/ crust and the 2/10 may be making the structure less sensitive to human triggers.

    Photo: Guy Zoellner

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Widespread recent snow accumulations of six to 14 inches occurred yesterday (Tuesday) across the region. Atypical winds from the North and East likely stiffened the snow in areas below ridgelines, saddles, or in cross-loaded, mid-slope terrain. 

    Avoid common trigger points, such as steep slopes immediately below a convexity. Moving surface snow may be relatively small and harmless, but it could push you over or through places not of your choosing. Pick slopes that are free from terrain traps below you, such as gullies, trees, or cliff bands. Keep in mind that a thin storm slab on a shaded slope may step down into a buried, deeper layer, resulting in a much larger avalanche.

    Move to gentler slope angles (less than 30 degrees) if you notice cracking in the surface snow, or test slopes are reactive to your weight.

    Soft slabs of recent or wind-driven snow are possible to trigger on all aspects and all elevations. Expect that the higher you climb, the greater the slab thickness. Avoid traveling above areas where you could be pushed into a terrain trap, such as a gully, roadcut, cliff, or mature timber.

     

Avalanche Discussion

Yesterday (Tuesday) produced widespread recent snowfall across the region. Thanks to anyone and everyone who performed a dance, prayer, or gear sacrifice. Your actions are appreciated by the greater skiing and snowmobiling community!

The Swan Range received nearly two inches of SWE and up to 14 inches of snow in the last 24 hours with light to moderate winds from the Southwest. The buried layer of surface hoar from late January remains sensitive in snowpit tests, and Blase and I remotely triggered a large avalanche on a north-facing aspect at 6,500 feet yesterday (Tuesday). Confirmation enough to remain far back from steep, shaded aspects.

The Flathead and Whitefish Ranges gathered six or more inches of snow yesterday. A natural running D2 was reported on Snowshed Mtn at an elevation of 7,000 feet, on a southeast aspect. Again, confirmation that the buried weak layer remains reactive. These slides follow multiple human-triggered slides reported Monday. Most of these were remotely triggered, and one caught and carried a skier near a ridge.

Steep slopes facing the sun, have been the go-to places over the last week to find refuge from the Persistent Slab problem. Right now, those same slopes are blanketed in fresh snow, creating a Storm Slab Avalanche hazard. The new snow is sitting on a stout melt-freeze crust that limits the chances of collapsing weak layers buried below it. 

Piecing together gentler slope angles should be the first step in avoiding avalanche problems today. Second, continue respecting the weak layers that remain on shaded slopes. Enjoy the abundant new snow, continue the dancing, and maintain spatial awareness in the mountains today.

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