Bulletin d’avalanche

Bitterroot

West Central Montana Avalanche Center
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Danger d’avalanche

Wed
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Points saillants

An intense, warm, and windy storm is overloading a snowpack with multiple concerning weak layers. Your chance of triggering avalanches will increase throughout the day as loading continues. Thick and wide slab avalanches breaking 1-4 feet down will be very easy to trigger and will release naturally. Avalanches may be triggered from long distances below, to the side of, and above steep slopes. Today is a day to steer clear of avalanche terrain, including the terrain exposed to avalanche hazard from above.

Much of the terrain in the Lolo Pass area falls into our lower elevation band (below 5,500'). However, there is much more snow here than in the rest of the low elevation in this zone, and conditions will be more dangerous. The considerable hazard rating at lower elevations in this zone is focused on the Lolo Pass area. 

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1.5–3

    Multiple weak layers are buried in the upper 1-2 feet of the snowpack. These layers produced human-triggered and natural avalanches prior to the intense storm that is taking aim at our region today. Up to one foot of dense snow (1" of snow water equivalent) has already fallen at upper elevations, and an additional 10-20 inches of snow (0.75-1.5 inches of snow water equivalent) will arrive by tomorrow morning. Our weak upper snowpack will not be able to handle this rapid load. 

    Avalanches will be very easy to trigger today, and many will fail naturally. Thanks to the layers of weak snow, these slides will break widely and will be able to wrap around terrain features and involve multiple starting zones. This produces very large, unpredictable avalanches with deep piles of debris. Importantly, you will be able to trigger these slides remotely — from a distance away from the slope that avalanches. This means that you can trigger slides that fail on steep slopes above you, and run down into flat terrain below. Avoiding this problem includes avoiding terrain threatened from above. 

    (2/19/2026)

    Buried surface hoar under 10 inches of recent snow.

     

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–2

    8-12 inches of snow have already fallen at upper elevations in this zone. An additional 8-12 inches are expected by nightfall. Avalanches within the new snow will be increasingly likely as the storm chugs on today. These will be largest and most sensitive in areas exposed to the wind, but can be encountered in sheltered terrain as well. These "smaller" avalanches will be plenty large to ruin your day or worse, and will be effective triggers for the larger persistent slab avalanches described above as they run downslope. 

Avalanche Discussion

With a heavy storm in progress, lots more snow on the way, and proven weak layers in the snowpack, my message for you is simple today: steer clear of avalanche terrain. We are not the fun police; we want you to come home safely at the end of the day. Today's storm is hammering the mountains with heavy, wet snow and moderate to strong westerly winds. Snowfall will continue throughout the day and overnight into tomorrow. It's already dangerous this morning, and your chances of triggering slides and encountering natural avalanches will only increase throughout the day. 

Over the last two weeks, smaller storms have built a slab on top of weak layers formed in January and February. These weak layers produced rounds of natural and human-triggered avalanches in a spotty distribution. The main ingredient lacking in the avalanche equation has been a strong slab over the weak snow underneath. Today's storm is rapidly changing that. Go into the mountains expecting to see plenty of signs of instability, including large natural avalanches. Avalanches will be easy to trigger and will be triggerable from long distances away from steeper slopes. Some slides will be large enough to snap trees and damage buildings. If you are going to ride and play in low-angle terrain today, take the time to make sure that you aren't exposed to avalanches releasing on steeper slopes above you. You can trigger today's avalanches from flat terrain below steep slopes. 

If you get out in the new snow today, take a minute to let us know what you are seeing out there. Your observations are a key component in an accurate avalanche forecast. Information about natural and triggered avalanches, the amount of new snow and wind, and riding conditions are all very helpful. Thanks in advance for giving your time, we appreciate you. Click here to access the observation submission page.

It has been a tragic week in the world of the snow. At least 13 people have been killed in avalanches in the Western US. You can find more information on these accidents here. Let's do everything we can to not add to that ghastly number. 

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