Lawinenlagebericht

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

A persistent weak layer near the base of the snowpack will remain as the main concern in our snowpack. This layer is found on all aspects above 4,500' in elevation. You can avoid triggering this weak layer by avoiding terrain that is steeper than 30 degrees and steering clear of open areas that lack vegetation to anchor the snowpack. 

Lawinenprobleme

  • Persistent Slabs

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

    We continue to see failure and propagation in a weak layer close to the ground. This weak layer consists of crust and weak, sugary snow. This layer is a result of the early November snow and a prolonged spell of cold, dry weather. Stability tests and observations are showing all the classic signs of instability such as collapsing and shooting cracks. Stability tests are producing propagation with light to moderate force. In areas where the snowpack is thin this layer is particularly sensitive, such as the Purcell Range and aspects where the wind has created thinner coverage. The snowpack in the Cabinets also harbors this weak layer but it has been shown to be less sensitive. This weak layer seems to be gaining strength over time but may still be triggered easily at treeline and above.

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Moderate winds out of the west and southwest were creating small pockets of windslab above treeline Monday. These slabs will likely continue to build throughout the day on Tuesday with moderate winds predicted out of the west. You can expect to find these slabs building directly below ridgelines and under steep, convex rolls at upper elevations. 

Avalanche Discussion

We are off to a great start this winter with good snow coverage considering it is still early December. We lack much of a base as the snow is pretty bottomless and there are plenty of obstacles to hit buried under the surface. I have also found it pretty easy to get the machine stuck at upper elevations if I grab a little too much throttle. One important thing to keep in mind at this point in the season with a deep weak layer is the high consequences of triggering an avalanche. Chances for trauma are very high when avalanches fail close to the ground.

Below are some recent photos of our weak layer and evidence of instability you are likely to see as you travel. Yesterday I was able to trigger cracks in the snowpack under steep road cuts and Sunday I felt multiple large collapses while touring on Flatiron. The snowpack is slowly gaining strength and becoming more resistant to triggers, but I am still avoiding steep terrain. Other observations of note is the layer of fresh surface hoar that grew over the weekend, I was able to find crystals that were 1-2 cm tall on all aspects at treeline and below. Time will tell if this becomes a problem when the next significant snowfall occurs.

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