Lawinenlagebericht

Silver Valley & Bitterroot Mountains

Idaho Panhandle 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 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Fresh snow and moderate winds gusting from the west and southwest direction will build wind slabs through the day, most likely on east and northerly aspects. This wind loading issue and the persistent weak layer are worth investigating before committing to slopes steeper than 35° today.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–3

    Facets around January’s Lucky Friday layer are still a concern today. Now buried 1-3’ deep, depending on location, a slide on this layer is a low likelihood, high consequence scenario. Recent stability tests have shown this layer to be stubborn, but I’m still skeptical. I believe it has the potential to propagate in the right situation, on big slopes near trigger points where the snowpack is shallow.

  • Wind Slabs

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

    Conditions will begin to change today as a modest shot of snow (4-8") and steady winds will transport snow onto north and east aspects creating small pockets of wind slab. Anticipate the potential for these slabs to become thicker, more reactive and of course more hazardous as the day progresses. Be on the watch for surface clues such as cracking in the snowpack. This will be your sign that slab development is occuring,  and it may be time to seek out more sheltered terrain and avoid areas that are steep and loaded by the wind.

Avalanche Discussion

On Thursday Kyla and Mikey toured the ridge above Copper Lake, just east of Lookout. Conditions were ideal with sunshine, light wind, moderate temperatures, and soft snow. 

Wind Slabs that formed with the strong winds during the storm early in the week will be less reactive today, but worth watching out for on start zones in steep terrain. Facets around the Lucky Friday crust layer and wind slab development are the biggest concerns today. With new snow falling, steady winds and a layer of surface hoar scattered across the landscape, you will really want to be attentive to surface conditions changing throughout the day. Today's conditions may be dynamic as the weather passes through. The crust layer was found buried over 100cm from the surface on northeast and west aspects below ridgeline. At that depth it is difficult to trigger as force is absorbed and bridged by the snowpack above it. However, where the snowpack is thinner, from wind scouring and settling on southwest aspects, a slide might still be possible. Triggering a slide on this layer is a low likelihood, high consequence scenario. Loose sluffs are definitely possible on steep slopes as well.

Wednesday’s cold clear night allowed the growth of widespread surface hoar. It’s not a problem right now, but if it gets buried intact we will need to keep an eye on it. We did find a layer of preserved surface hoar feathers mixed with graupel about a foot from surface. It did not show a willingness to propagate in our pit tests, but we will have to see how it reacts to the new snow forecast for the area in the coming week!

On that note, big weather changes coming Sunday night through Wednesday morning. National weather service is predicting abundant snowfall and winds followed by and arctic intrusion on Wednesday. So, be alert for big shift in avalanche stability early this coming week. 

Thank you for submitting an observation!

There is still time to sign up for a FIPAC Rec Avy 1 class at Silver this weekend and Schwitzer the first weekend in March.

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