Bollettino valanghe

Selkirk 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 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Weakness in the storm snow that accumulated from Sunday into Sunday night could produce loose sluffs in steeper terrain.  A buried surface hoar layer under the Lucky Friday crust could produce an avalanche in steeper terrrain.  Both of these problems are not likely due to lack of a cohesive slab in the storm snow and the surface hoar weak layer residing under a breakable crust.   But in the right/wrong place they could get you into trouble.

Problemi valanghivi

  • Storm Slabs

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

    My old partner Eric Morgan and I had a great tour around Lunch Peak yesterday hitting every aspect.  We found light powder surface conditions on all aspects but there was just enough reaction in the storm snow due to a change in density that we decided to stay off slopes steeper than 35 degrees.  We did not see evidence of wind but wind could slab this new snow to create a firmer layer on top, making it more prone to slide.

  • Persistent Slabs

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

    A crust formed last Friday the 13th when rain fell in the mountains and then froze.  That's why I'm calling it the lucky Friday crust.  Surface hoar remained intact underneath.  In shear tests the layer failed with moderate force applied but this is after I have cut through the crust.  So, the crust will give us some resistance to the weak layer below it but it is a breakable crust.  Steep slopes in complex terrain or steep convex slopes are the places I would not feel comfortable about this layer, especially on north aspects where the crust is thinner.  It is tough to know all the variables with this problem so it's easier to dial back your terrain selection.

Avalanche Discussion

Although it has been wet and dreary down low the high country has been getting gradual accumulations of snow.  Recall the rain of last week and then how the temperatures dropped just enough to get the white stuff above about 3,500 feet.  You'll notice this buried Lucky Friday crust layer with about one foot of light snow over it on all aspects.  The snow has bonded well to the crust but weak layers in the new snow above and the surface hoar below are our current, but manageable problems.  On a NE aspect we found just the right combination of trees, slope angle and snow depth to get a good quality check after digging pits on south, east, and west aspects.  There's alot of steep terrain off Lunch Peak, and plenty of powder but we didn't feel confident enough in the stability of those two weak layers to take a chance.  The picture you see is north of Lunch Peak with gentle slopes in the foreground and the type of terrain that I would be careful on today in the background; steep and convex.  If you or someone you know is between the age of 14-24 and want to take an avalanche class consider applying for the Doug Abromeit Avalanche Scholarship.  The deadline is March 15 so there is still time to submit and win a free level 1 avalanche class.  https://www.idahopanhandleavalanche.org/doug-abromeit-avalanche-scholarship

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