Bollettino valanghe

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Generally stable snowpack conditions exist below treeline. At upper elevations you will find north and east facing slopes have been loaded by recent snow and southwest winds. Terrain directly below ridgelines is where this problem can be found. It is possible to trigger small wind slabs in steep terrain below ridgelines on north and east aspects today.

Problemi valanghivi

  • Wind Slabs

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

    Recent snow and moderate winds out of the southwest have created small and stubborn wind slabs directly below ridgeline. With additional snow and wind on predicted onTuesday, these wind slabs will continue to build through out the day. Triggering a wind slab can be easily avoided by steering clear of steep terrain (steeper than 35 degrees) on these aspects. Recent forecaster observations show that wind slabs are more prevalent and reactive in the East Cabinets, versus other ranges within the Kootenai forecast area. 

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3

    Facets above the January 13th rain crust are still showing signs of weakness at upper elevations on aspects with a thinner snowpack. The past two weeks we have been seeing propagation in this layer on south and west aspects near treeline. On north and easterly aspects this layer can be found, but is not showing much potential for failure.  In most locations, it is buried approximately 2-3 feet below the surface and will have enough volume to kill or injure a person if triggered. Triggering this layer is a low-likelihood, but high consequence scenario. Avoid large open slopes that have a thin snowpack, this will minimize your exposure to this problem.

Avalanche Discussion

On Monday, Nate and I toured into the West Cabinets just south of Troy. Fresh snow that fell on Sunday blanketed all of the gnarly and firm wind affected snow from last week. The new snow made for some really good riding and skiing conditions. Stability tests are showing a stable snowpack other than the "persistent weak layer," that continues to persist (true to it's name).  The new snow was obviously loaded onto slopes just below ridgelines and into small pockets that were pretty darn stubborn and difficult to trigger. On Sunday, Nate spent the day in the East Cabinets and noted that the new snow was more reactive and slabby at elevations above treeline. If you are looking to trigger a wind slab, then steep terrain of the East Cabinets is where you can find trouble, if that's what you seek. In very steep terrain we were also able to generate a fair bit of sloughing in the new snow on northerly aspects as well yesterday, but the "loose-dry" problem is pretty minimal and easy to manage.

Last week we saw a nice shot of fresh snow followed by cold air and stout winds out of the north and east. This developed some pretty impressive wind slabs that were easily triggered last week. Eventually the winds hammered the snow until it was as stiff as a board. This firm and wind-hammered surface can be felt still in many locations under the new snow. The wind slabs that developed last week are very unlikely to be triggered at this time and have fallen off my list of avalanche concerns. For the upcoming week we seem to be back in a winter weather pattern, with consistent and small doses of snow and seasonal temperatures. This pattern should bode well for snowpack stability if we can avoid any wild swings in weather. Wild temperature variations, strong winds and rapid loading are not good for snowpack stability, so hopefully we can stay in a consistent pattern that keeps the snowpack stable and the snow fresh.

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