Bollettino valanghe

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Persistent weak layers consisting of Facets and Surface Hoar exist in the upper 1.5 feet of snow on Northerly aspects above an ice crust.  The Facets near the ice crust were more sensitive to tap tests and evidence of recent naturals shows that there is potential for layer failure on steep exposed terrain in the upper elevations with the right trigger in the right place.  Spatial variability will be something to keep in mind during your travels.  

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    In the Purcells yesterday, the primary concern found was a faceted weak layer just above the mid January icecrust (15 inches deep) where a thin weak ice crust is breaking down and failing easily on compression tap test.  A stubborn Surface hoar layer with no results on compression tap test is prominent in the Purcells about 8 inches down from the surface.  We did not get any propogation results on our extended column tap tests but did observe recent avalanche activity since the last storm a week ago on these weak layers with the ice crust acting as the bed surface for the avalanches.  

Avalanche Discussion

Steep and exposed terrain in the upper elevations has had recent avalanche activity within the past week as observed in the upper elevations in the Purcell Range.  The weak layers where the activity has taken place were found in pit tests but becoming more stubborn due to the healing time since the last storm and warmer temperatures.  One of the avalanches occurred from the trigger of an ice/snow release from a tree that was strong enough to trigger an avalanche on an exposed NE slope at 6000 feet.  One may gain confidence as they may not see results but should use caution understanding that if you hit the sweet spot, there is a prominent weakness in the upper 2 feet of the snowpack and is therefore easy for a skier or sledder to trigger.  As the surface hoar seems to be healing, it should be noted that the facets near the ice crust continue to build and weaken near that crust which was thinner and weaker in the Purcells than in the other ranges I have observed in the past week.  The East Cabinet observations relayed to us were very similar to the conditions in the Purcells with emphasis on the collapsing on surface hoar and facets below treeline on North and East aspects and ridgeline.  

Regioni coperte