Bollettino valanghe

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Sun
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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In sintesi

Wet loose avalanches that are large enough to bury a human will be very likely today. Avalanche hazard will increase through the weekend on slopes that are exposed to the sun as temperatures increase through Sunday. Minimize your exposure to this hazard by travelling on ridgelines and avoid being in terrain steeper than 30 degrees. Avoid stopping or travelling in avalanche run-out paths today.

Problemi valanghivi

  • Loose Wet

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

    The sun will be out in full force today with temperatures at upper elevations predicted to reach the 50's. With abundant amounts of soft snow on the snowpack surface it is very likely that wet loose avalanches will be releasing naturally today and will be large enough to bury a skier or snowmobiler. While these loose avalanches are often perceived as relatively harmless we need to give them a little more respect this weekend as temperatures get progressively warmer. This problem will become even more of a concern by Sunday as overnight lows may fail to drop below the freezing mark and daytime highs continue to climb. You can avoid wet loose avalanches today by avoiding slopes exposed to the sun, especially in the afternoon hours. Safer conditions and better snow will be found in terrain that is north facing or shaded in low angle timber.

    Photo: Ben Bernall

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3.5

    During the past week our stability tests and snowpack analysis have produced few results and reveal a snowpack that appears to be improving in both strength and stability. The layers of note include a thin layer of buried surface hoar found on north aspects under the last storm snow, the early February crust layer, and a thin melt-freeze crust found roughly 12-18" above the February crust. While none of these layers have proven to be much of a concern the past week, that could all change as warm temperatures and sunshine weaken the upper snowpack and create the potential for slab avalanches on all aspects above 5,500', these slabs will be more likely to fail in terrain exposed to the sun. These layers and their potential represent one of the more challenging aspects of avalanche forecasting as it can be hard to predict if, when, or how they will fail under this warm spell. Regardless, the potential for a wet loose avalanche to step down and create a large and destructive avalanche on one of these persistent weak layers will increase through the weekend. 

Avalanche Discussion

On Thursday we toured into the East Cabinets under partly sunny skies, some of us brought sunglasses, some of us forgot them at the truck. We found firm conditions at lower elevations left behind by the warmer temperatures and rain that fell Sunday through Tuesday. We observed one recent "climax avalanche" that released on bed rock and multiple D2 sized avalanches that had released in steep terrain at tree line and above in the last storm snow. While our snowpack structure could be perceived yesterday as being in pretty stable condition it is really important to recognize the transition we are making in overall weather pattern going into the weekend. Snowpack stability generally declines when we see a drastic change in weather conditions, with sunshine and temperatures predicted to be 10-15 degrees above the seasonal norms there is a going to be some snow moving down the hill this weekend. Spring weather often brings a different brand of avalanche animal and a shift in hazards. The next few days we will see loose wet avalanches, wet slabs failing on deeper weak layers, cornice failures and glide cracks become the primary concerns in the mountains. While avalanches will be very likely in steep terrain under these spring conditions the problems are easy to manage by paying attention to aspect and time of day. If you avoid being on or below steep slopes exposed to the sun as temperatures rise, you can steer around potential avalanche problems.

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