Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

New snow and wind have likely formed one- to two-foot slabs that will be sensitive to a rider's weight. Low-angled terrain sheltered from the wind will offer the best and safest riding. A small avalanche or a cornice fall could trigger a much larger and more dangerous persistent slab avalanche. The higher you travel, the more conservative your terrain should be.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Recent storm snow and moderate southwest winds have built fresh slabs that will be sensitive to a rider's weight. Recent snow totals favored the Swan and Flathead Ranges, so we expect a more widespread new snow avalanche problem in those zones. Slabs will be thicker and more dangerous downwind of ridges, saddles, and on the sidewalls of gullies. The new snow landed on crusts or possibly a weaker snow surface, which could result in a more widely propagating slab avalanche.

    Avoid dune-shaped drifts or pillowy-looking surfaces. Those indicate a recently formed wind slab. Use small, inconsequential test slopes with a spotter to assess the sensitivity of freshly fallen snow. If you see shooting cracks or trigger small avalanches, know that conditions are ripe for triggering on slopes with similar characteristics.

    Loose Dry: In terrain sheltered from the wind, or on previously sunbaked slopes, you may see a loose dry avalanche problem. Utilize defensive riding strategies by allowing your sluff to run next to you, not over you. Sluffs may travel far and fast on previously formed crusts.

    (3/28/2026)

    An avalanche that failed as a result of wind loading. Expect avalanches in terrain with similar characteristics today. 

    Photo: Lydia Willoughby

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    The most surefire way to manage this problem is to travel on slopes where the problem doesn't exist. You can generally avoid this problem by riding on slopes facing south or west. We also suspect a surface crust and previous warming make it very unlikely that this problem exists below about 6500. Below that elevation, your primary objective in managing this problem is to minimize overhead hazard.

    Uncertainty grows on shaded aspects at upper elevations. We continue to find the weak layer intact and looking just like it did three months ago. Now it is buried deep and has a history of propagating thousands of feet wide and breaking several feet deep. Although we suspect the likelihood of triggering is trending to unlikely, the consequences are such that we still don’t recommend traveling on steep, upper-elevation, shaded slopes. A falling cornice or a smaller wind slab is a ripe trigger for one of these beasts.

    (3/17/2026)

    Windslab activity at ridgeline that resulted in a larger, very destructive slab avalanche that failed on buried persistent weak layers. 

    Photo: Michael Reavis

Avalanche Discussion

Old Man Winter made a return. Across the region, five to 10 inches of new snow fell in the past 24 hours. Snow densities appear to be less than 10%, which may make for superb riding conditions today. If you are aiming to get some of your last powder riding in for the season, be sure continuously assess new snow instabilities and thoughtfully manage your overhead hazard. 

You may experience a range of “new snow” avalanche problems. I’m confident you’ll find wind slabs downwind of terrain features. Winds will diminish later in the day, so use surface clues to guide your route selection for managing those. In sheltered terrain, you’ll have to manage a storm slab or a loose dry avalanche problem. New snow totals will likely dictate which one you’ll have to manage. Assessing that on the fly will be fairly simple by paying attention to cracking around your boards or machine. 

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