Boletín de aludes

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

A buried persistent weak layer is widespread and still showing signs of instability in the southern Purcells.  Triggering and avalanche on this layer is still possible in steep, open terrain.  Consistent northerly winds were strong enough to redistibute snow at mid and upper elevations forming fresh windslabs in leeward terrain.   If triggered, windslabs will have potential to step down to the buried persistent weak layer. 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    The persistent weak layer consisting of a rain crust/facet combination is present across the forecast zone and continues to fail and propagate in stability tests with moderate force in the Purcells.   In the Cabinets this layer is buried deeper and is stubborn or unreactive in tests.  It is still possible to trigger small to large avalanches in steep, un-anchored terrain on this layer,  especially in the Purcells where the snow pack is thinner.  Look for classic signs of collapsing and whumphing and seek sheltered or lower angled terrain if in doubt.  

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Winds out of the North have redistibuted snow and are forming wind slabs on South facing terrain at mid and upper elevations.  Avoid areas of blowing, drifted, or "pillowed" appearing snow  to manage the windslab problem.   Snow that feels stiffer underfoot or produces shooting cracks are indicators of windslab development.  Wind slab avalanches have potential to step down to deeper weak layers present in the snowpack.

Avalanche Discussion

Snow depths and reactivity to triggers varies widely across the Kootenai Zone right now, making it hard to apply a one size fits all approach.  The persistent weak layer formed around the November rain crust is present across the area but is proving to be stubborn in stability tests in the West Cabinets, but alive and well to the north in the Purcells.  In the southern Purcells the classic signs of audible whumphing and collapsing were still on display throughout the day and should continue to influence terrain selection when travelling near avalanche terrain.  A layer of surface hoar buried 5-6 inches down is present and did not propagate, but its worth keeping an eye on. Forecasted cold temperatures and minimal snow accumulation in the coming days will likely preserve any persistent weakness, ie.  suface hoar and facets, where they are present, and will bear keeping in mind as we move into the next storm cycle.  Windslabs may continue to form in unusual locations and some vigilance may be needed to manage this problem.  Presently there is great riding in sheltered terrain and given the variability across the zone, I would personally take a conservative approach to stepping out into exposed terrain where the possibilty of waking up our "persistent" buried weaknesss could have detrimental consequences.  

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