Bollettino valanghe

Elkhorns

Wallowa Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A week of uneventful weather combined with a stout surface rain crust at most elevations is contributing to low danger at treeline and below.  A weak weather system over the next 48 hours will bring light precip (2-3" snow)  and light SW winds to most locations above 5,000'. Expect dust on crust conditions and the possibility of dry loose slides on slopes > 35 degrees. Shallow pockets of reactive wind slab may be encountered on > 35 degree slopes on N-E aspects below ridgeline and cross-loaded terrain features mid-slope. We continue to observe weak persistent grain types in our snowpack. At this time the likelihood of triggering an avalanche on these weak layers is low but the consequences of such an avalanche could be high.  Conservative terrain selection is warranted, where and if, the surface crust is penetrated. This is especially relevant for snowmobilers.

Problemi valanghivi

  • Wind Slabs

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

    It may be possible for skiers or riders to trigger shallow pockets of recently deposited wind slab on steeper (>35 degree) slopes mostly on N-E aspects near ridgeline. The rain crust from last week exists well into the alpine in most mountain locations. Any new snow (2-3") will be easily transported by light SW winds and deposited on this slick bed surface. The new snow will not bond well to this stiff crust and will likely slide easily. Avoid wind-loaded terrain features below ridgeline and cross-loaded gullies and ribs mid-slope. Look for rounded smooth and stiff pillows of snow or shooting cracks around these features and avoid them to prevent a slide for life scenerio. 

  • Persistent Slabs

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

    We are still seeing the Solstice Rain Crust and associated facets in our snow pits and this layer still lingers close enough to the surface to be affected by the weight of a recreationalist where and when you are able to penetrate the stout rain crust from last week. The resulting avalanche would be large and destructive. While the weight of most skiers and snowboarders will not be significant enough to penetrate the rain crust, snowmobilers on the other hand, may be able to bog down and impact persistent weak layers buried 2-3 feet down. In the Southern Wallowas the SRC is down about 4 feet. If riders find themselves penetrating the rain crust and impacting deeper layers in the snowpack, then terrain choices should become more conservative by dropping your slope angles below 35 degrees. 

Avalanche Discussion

A semi supportable rain crust exists at all aspects and elevations. The thickness of the crusts vary from location to location. Snow depth varies from place to place. In some areas the snow is over 6' deep. Other areas are holding 4' of snow. Structurally, the Solstice Rain Crust is down about mid pack. The SRC is a multi layer crust/facet sandwich. It rests upon facets that are consolidating and therefore gaining strength.  Above the SRC the snowpack is mostly right-side-up.  The new snow will not bond well to the stiff surface crust and will likely slide easily. This presents us with a potential for shallow (2-4") loose dry avalanches on slopes >35 degrees. While these slides are unlikely to be enough to bury a person, they could potential cause a slide for life situation. Be careful on slopes >35 degrees where a potential slide could cheese grate you through the trees or pound you into rocks. 

Regioni coperte