Bollettino valanghe

Blues

Wallowa Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Up to 5" of new snow and associated southwest winds have built fresh sensitive windslabs along exposed upper elevation terrain.  As your exposure to the wind decreases in more sheltered terrain, storm slabs are possible where the new snow has fallen on either a surface of the Solstice Rain Crust, or wind blown pockets of snow from 12/22.  

Problemi valanghivi

  • Wind Slabs

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

    The Milk Shakes Snotel (5600') is reporting 5" of new snow with .7" of SWE (Snow Water Equivelent)   The new snow, along with winds in the moderate to strong category, have formed fresh sensitive windslabs along leeward ridgelines and cross loaded terrain features.  Observe localized wind loading patterns and avoid slopes that look like they have smooth and rounded surfaces.  Utilize small inconsequential test slopes to test the reactiveness of these windslabs.  Even a small windslab in the wrong location (think above terrain traps), could bury and/or injure a rider. 

  • Storm Slabs

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

    While recent limited observations have indicated that the snowpack in the Blues is more consolidated than other WAC forecast zones, our secondary concern to windslabs will be storm slabs failing on the mixed bag of surfaces.  In wind blown areas, the surface was the shiny Solstice Rain Crust.  In wind deposited areas, the surface was a mix of surface hoar and/or graupel.   See pictures below from 12/23 at Spout Springs. 

    Quick hand pits to test the reactiveness of this new/old snow interface will give you a great idea of how these layers are bonding together.  If you get clean shears by pulling the new snow off the old surface, storm slabs are likely.   Small, safe test slopes are also a great way to test the reactiveness of this interface.  I would expect any sensitive storm slabs to stabilize over the next couple of days.  

    (12/23/2020) Consists of Graupel and Surface Hoar

Avalanche Discussion

Observations are limited in this area, and although a persistent slab isn't listed in the avalanche problems for this zone, I haven't ruled it out completely.   In your travels, dig down a couple feet and look for strong cohesive snow over weak sugary snow.  On 12/23 at Spout Springs on a west aspect at 5300 feet, observers found a quite uniform snowpack without much difference in hardness amongst the layers.  This is just one data point, so evaluation of the hardness profile in the snowpack is recommended to observe for a slab over weak snow.   If these conditions exists, choose lower angle, and more simple terrain for your recreation or travel.  

Regioni coperte