Lawinenlagebericht

Bitterroot

West Central Montana Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Strong sunshine and warm temperatures will make wet loose avalanches likely today. Larger, destructive avalanches resulting from cornice fall and lingering buried weak layers are possible. As slopes become wet, move to lower angle and shaded slopes, and be aware of the terrain above you. Consider digging down to look for poor snowpack structure before committing to avalanche terrain. 

Lawinenprobleme

  • Cornices

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–3

    There are many large overhanging cornices along upper elevation ridgelines. Cornice failures can be hard to predict, but today’s sunshine and warm temperatures are a good recipe to destabilize them. Give cornices a wide berth and avoid hanging out underneath them. Cornice failures could also trigger large slab avalanches on the slopes below. 

    (2/28/2025) Avalanche triggered by cornice fall, SE aspect of Lappi point, ~7400’, 35-45 degrees

  • Loose Wet

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

    Human triggered wet loose avalanches will become likely on sun affected slopes today. Last night, temperatures dropped below freezing in most areas, so surface crusts will be present this morning. The combination of strong sunshine, light winds, and temperatures possibly reaching into the 50s at upper elevations today will quickly break down the crusts. In isolated areas, temperatures remained above freezing last night, and the snow may not have refrozen. 

    Rollerballs and point releases are signs of wet snow instability. If you find yourself in mushy, wet snow or see natural, wet loose avalanches, it is time to step back out of avalanche terrain and be aware of what terrain is above you. You can also move to cooler, shaded slopes to find drier snow. Remember that even small avalanches can have serious consequences. Also, smaller wet loose avalanches could step down and trigger larger wet slab or persistent slab avalanches in areas with poor snowpack structure.

  • Persistent Slabs

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

    It remains possible to trigger a large persistent slab avalanche that fails on weak layers buried 3-5 feet deep. Although the problem has been trending towards better stability, pockets of reactive slab remain, and warm temperatures could reactivate it. 

    Observations have shown intermittent propagation in tests, but don’t let that fool you into thinking there is no danger. There may be no red flags before a large avalanche occurs. You are more likely to trigger one of these persistent slabs in areas where the snowpack is thinner, like around rock bands or convex rollovers. 

    To identify the problem, you can dig down in the snow and look for poor snowpack structure with a slab above weak snow. Even if snowpit tests are unreactive, poor snowpack structure should be enough to give you pause before committing to avalanche terrain. Stick to slopes under 30 degrees in slope angle and without steep terrain overhead if you simply want to avoid the problem.

Avalanche Discussion

Happy March! Although today’s weather makes it feel like it’s already April… It will be another gorgeous, warm, sunny day. Compared to the last few days, today will likely be less windy, which could lead to even more warming of the snowpack, especially in previously wind exposed areas at upper elevations. 

Depending on aspect, elevation, and time of day, snow conditions are currently quite variable, leading to a variety of potential avalanche problems to manage. Wet loose avalanches are the smallest, but also the most likely. Cornice fall and persistent slabs are harder to predict but could result in large and destructive avalanches. 

Recent observations have found glide cracks opening up on a variety of slopes. The warm weather will make these glide cracks more likely to fail. Avoid traveling below slopes with glide cracks, as they can unpredictably release the entire season’s snowpack. 

If you travel up to the highest peaks, isolated, small, hard wind slabs are also a concern from the last few days of strong west winds. Look out for fresh wind pillows and drifts, and red flags like cracking and collapsing. 

Join us next week at one of our events! Sip for a cause at our Pint Night Fundraiser on Wednesday evening from 5-8 pm at Imagine Nation Brewing Company in Missoula. We are also hosting a Mountain Weather Workshop on Thursday evening for our members. Not a member yet? No worries—sign up today by visiting our membership page to gain access. In addition to supporting the avalanche center, you'll receive perks like discounts, newsletters, and additional online resources. 

Please continue to submit observations and help us keep an eye on changing conditions. Check out this video on what makes a useful observation. 

Avalanche forecasts will be issued on Saturdays and Sundays. A general information product will be issued on Mondays to cover the Monday-Friday period. Additional forecasts will be issued anytime an Avalanche Warning is issued.

Ski and ride safe.

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