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

Although cooler temperatures are helping stabilize the snowpack, skiers and riders could still trigger large and destructive wet slab avalanches. Consider sticking to low angle slopes to give the snowpack more time to strengthen. If you are sinking through an unsupportable surface crust, then wet slabs are more likely. 

This weekend will be our last weekend of regularly scheduled forecasts. We will issue our last scheduled product on Monday, March 31st, and will update the product through April when conditions warrant.

Lawinenprobleme

  • Wet Slabs

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

    Last night was the first decent refreeze in several days for many locations. This has significantly reduced the chances of triggering a wet avalanche. However, below last night’s refrozen snow, there is still significant water and heat lingering deeper in the snowpack. It will take time for that deeper snow to stabilize. Until it does, there is still a chance of triggering a wet slab avalanche. These avalanches could be very large and destructive, as evidenced by these wet slab avalanches in the Swan Range earlier this week. 

    Wet slabs are notoriously unpredictable. They destabilize when meltwater percolates down in the snowpack and pools near weak layers and crusts. If you are still finding wet snow, even if it’s buried below a surface crust, large to very large wet slab avalanches remain possible. They are more likely in areas without a supportable crust at the surface. Consider giving the snowpack more time to heal by sticking to low angle slopes.

Avalanche Discussion

This week was a period of rapid change for the snowpack. The week started with significant rainfall and was followed by well above average temperatures and multiple days without a solid refreeze at night. A widespread natural wet avalanche cycle occurred during that period. Wet avalanches were reported on all aspects and at all elevations. Wet loose avalanches were the most abundant, but large gouging cornice failures also occurred, and several very large wet slab avalanches were observed in the Swan Range. We’ve received limited observations this week (apparently it’s bike season!), but I suspect that there were also significant wet slab avalanches in other parts of the region. 

The weather pattern began to change yesterday to a cooler and snowier pattern. Last night, we saw the first decent refreeze in several days for many locations. This will help the snowpack gain strength and stabilize, but that process takes time. With significant heat and wet snow still buried in the snowpack, we can’t rule out wet slab avalanches yet. 

The pattern change will also bring the possibility of fresh avalanche hazards in the new snow. Accumulations this weekend will generally be light and are forecast to favor the southern part of our region. Most places will likely just have dust on crust conditions, but the light snow and light to moderate winds could build small fresh wind slabs at the highest elevations today and tonight. If you find pockets of wind drifted snow 6 inches deep or thicker, wind slabs will be possible. Wind slabs can be identified by their smooth pillow like appearance, by shooting cracks around your skis or snowmobile, or by a firm hollow feeling slab of fresh snow. If you find any of these, you can stick to slopes less than 30 degrees in slope angle to avoid avalanches. Remember that even small avalanches can have serious consequences. 

Glide cracks have opened up on isolated slopes throughout the region. Glide avalanches are very difficult to forecast or understand due to their unpredictability. The time between a crack opening up and the avalanche failing can vary from minutes to months. Avoidance is the answer. If you see open glide cracks, do not travel underneath them. 

The cooler weather will help stabilize overhanging cornices. However, that process can take time. If you see overhanging cornices, it’s always a good idea to avoid traveling underneath them. Cornice failures can gouge down and trigger large avalanches on the slopes below. 

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!

Every Public Observation you submit through Missoulaavalanche.org after March 8th, 2025 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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