Lawinenlagebericht

Bitterroot

West Central Montana Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Human triggered wind slabs will be possible today anywhere 6 inches or more of new snow has fallen or drifted into a slab. A wind slab can be identified by its smooth, pillow-like appearance, hollow feel, or by shooting cracks around your skis or snowmobile. If you see any of these, avoid the problem by sticking to slopes less than 30 degrees in slope angle.

Triggering a larger persistent slab avalanche is unlikely, but specific pockets of weak snow remain in rocky terrain and on convex rollovers. You are unlikely to see any red flags before the avalanche fails unless you dig in the snow to look for weak sugary snow with a slab above.

Avalanche danger could rise to considerable tonight into early Sunday morning as new snow totals ramp up overnight.

Lawinenprobleme

  • Wind Slabs

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

    4-5 inches of new snow today combined with gusting southwest winds will build fresh wind slabs on easterly aspects. These fresh slabs will be sitting on lingering wind slabs 2 days old that formed during Thursdays upper elevation wind event. Triggering an avalanche large enough to catch and carry you will be possible anywhere you find 6 or more inches of wind drifted snow. At mid elevation, these slabs will be sitting on a bed of firm snow, and even small avalanches have potential to run fast on buried crusts. 

    To identify wind slabs, look for areas of smooth or pillow-like snow. If you poke or dig into the snow and find a slab at the surface with a hollow feeling, or see cracking around your skis or sled, you've likely found a wind slab. 

    To avoid wind slab avalanches, stick to slopes under 30 degrees in slope angle, or terrain unaffected by blowing snow and wind.

     

     

    (3/12/2025)

    A small intentionally triggered wind slab on an upper elevation east aspect in the Rattlesnake

    Photo: Arden Feldman

  • Persistent Slabs

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

    Triggering a larger persistent slab avalanche that fails 3-5 feet deep has become unlikely. Specific pockets of poor snowpack structure remain with buried January facets, and facet crust combinations.

    This problem still lingers in areas with rocky convex rollovers, however, even in these areas snowpit tests have become increasingly unreactive. You are unlikely to see any red flags like shooting cracks, whumphs, or feel collapsing before an avalanche occurs. 

    If you find weak or sugary snow with a slab above, avoid the problem by skiing or riding elsewhere.  If you choose to ski or ride that area, stick to low angle slopes, avoid convexities, and avoid likely trigger areas.

Avalanche Discussion

A storm is arriving today, bringing increasing winds and new snow. For today, most of the moisture looks to miss us to the North, impacting the Flathead area. Snow totals for today in West Central Montana range from 4-7 inches. Tonight the storm ramps up with larger snow numbers expected by Sunday morning. 

Spring conditions vary between melting, melt-freeze cycles, and cold and snowy. We’ve been in a melt-freeze or melting pattern for the past week. Today we see that shift into a cold and snowy pattern that continues into next week. With the change in pattern comes a change in mindset back to winter conditions and looking for signs of instability in the new snow. 

We are not anticipating a valley rain event today, but spring weather can be unpredictable, and if you find yourself in a rain on snow situation at low elevation, be alert for signs of wet snow activity like rollerballs or point releases. 

Win a Garmin inReach Mini 2 – Support Your Avalanche Center with Every Observation!

We’re excited to offer a fantastic opportunity to win a Garmin inReach Mini 2 simply by sharing your field observations with us!

Starting today, Saturday, March 8th, 2025, every Public Observation you submit through Missoulaavalanche.org automatically enters you for a chance to win this excellent, compact satellite communicator.

The winner will be drawn on May 2nd, 2025, during Missoula Gives!

Each Public Observation counts as an entry, so the more you submit, the better your chances of winning! Your valuable observations are crucial in helping us provide accurate avalanche forecasts, ensuring everyone stays informed and prepared for safe, enjoyable backcountry adventures.

Thank you for your continued support of the West Central Montana Avalanche Center. Submit your observations for your chance to win and positively impact your forecast!

Ski and ride safe.

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