Bulletin d’avalanche

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Wednesday's warm temperatures and rain created a stout 2-4 cm rain crust up to 5500' on the snow's surface.  Thursday's observations revealed dry loose snow beneath the breakable crust in the Purcells.  The crust is thinner at the upper elevations where 6-12" of dense snow lies on top of a widespread surface hoar layer.  Human triggered avalanches are possible in steep terrain that may be easily triggered if surface hoar is buried beneath the dense new snow. Avoid steep windloaded terrain and convex terrain features over 30 degrees. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    The wind has been predominately out of the SW the past few days, therefore windslab development is likely on upper elevation NE aspects.  In both the Cabinet and Purcell ranges we observed up to 1cm tall surface hoar which developed last weekend and is buried under a dense slab from the rain/snow event Wednesday.   Windslabs may be triggered if they rest upon this surface hoar layer.  Be aware of cracking, whumphing, and hollow sounding snow. Take the time to dig pits and assess whether the surface hoar is present before riding on or below avalanche terrain.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Wednesday's storm brought rain to the low elevations and heavy, dense snow to the upper elevations.   In both the Cabinet and Purcell ranges we observed up to 1cm tall surface hoar which developed last weekend and is buried under a dense slab from the rain/snow event Wednesday.   The storm slab may be triggered in steep terrain where surface hoar remains intact.  Take the time to dig pits and assess the snowpack prior to venturing into avalanche terrain.

Avalanche Discussion

The lower elevations received a lot of rain of Wednesday so there is a 2-4 cm breakable rain crust up to 5500'.  FUN!  This will be a good sliding surface for the next round of snow that falls. 

The main concern in our current snowpack is a layer of surface hoar that remains intact at various aspects and elevations in both the Purcells and Cabinets.  The storm snow from Wednesday's rain/snow event rests on top of this surface hoar layer.  Human triggered avalanches are possible at the mid and upper elevations in steep terrain and on windloaded aspects.  Take the time to dig pits and determine if the surface hoar layer is present before skiing or riding in avalanche terrain.  We observed propagation in our extended column tests on Thursday on NE and E aspects.  This is an indicator that the current slab is strong enough to be triggered by skiers and snowmobilers in steep terrain.

Régions couvertes