Bollettino valanghe

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Wed
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Persistent slabs and lingering wind slabs are unlikely but not impossible for you to trigger. Today is a prime example of Low avalanche danger not meaning no avalanche danger. Consider these unlikely but not impossible avalanches and their potential consequences as you choose appropriate terrain. Your beacon, probe, shovel, and avalanche brain are still necessary equipment for travel in the backcountry. Continue to use your safe travel practices in avalanche terrain, like moving one at a time from safe zone to safe zone, as you take in a little sunshine and unseasonably warm temperatures in our mountains.

Problemi valanghivi

  • Persistent Slabs

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

    The surface hoar that was buried with new snow a little over a week ago seems quite variable in distribution and sensitivity but could still produce human triggered avalanches in isolated areas. These areas seem to be wind protected open areas on the northern half of the compass rose, which is where the largest surface hoar was likely buried. Think mid-slope openings in the trees. Remember that surface hoar can produce avalanches on slope angles as mellow as 30 degrees or slightly less. Thoroughly investigate or avoid these select areas where this persistent weak layer may still be found. The most recent reported avalanche activity on this layer occurred this past weekend immediately east of our forecast zone on Taft Peak.

    (2/6/2022)

    Avalanche, likely human triggered, NNE aspect, 5200', on Taft Peak (immediately E of our St. Regis & Silver Valley forecast zone).

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Wind slabs that are mostly small developed from new snow late last week and seem slow to bond to the older snow. They’re stubborn to human triggers but not entirely stable yet. These isolated wind drifts are somewhat firm and tend to be located on easterly aspects near exposed ridges. Other than these pockets which are likely only a concern on steep, convex features, it’s a good time to take advantage of the relatively stable conditions above treeline.

    (2/7/2022)

    An example of the small, stubborn, but not entirely stable wind slabs lingering on the lee side of some ridges.

    Photo: Ryan Matz

Avalanche Discussion

Human triggered avalanches have become unlikely overall, but isolated instabilities remain. The surface hoar layer that’s now about a foot below the surface has only been producing avalanches and signs of instability in isolated areas. It hasn’t gained much or any strength though this may improve with the extended period of warming this week. Our still stubborn wind slabs from late last week are more likely to gain stability through this week. At low elevations, the warm weather is beginning a melt/freeze cycle reminiscent of spring conditions and making loose wet sluffs possible at the warmest times of day. Deeper in the snowpack, the January 12th rain crust is still prominent and does have some weak, faceted snow around it, but inconsistent stability test results and no reported avalanches on this layer keep our concerns to a minimum.

All this is a good reminder that a wide range of conditions can fall under a Low avalanche danger rating, and while avalanches are unlikely, we don’t have a truly stable snowpack. Realize that our spatially variable avalanche problems still linger and that we’re pushing the upper end of Low avalanche danger as you enjoy the warm weather this week!

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