Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

You could trigger an avalanche in steep, wind-loaded pockets after a foot of cold, low-density snow came in with wind on Sunday. Search for surface clues both under your feet and from a distance, to identify thicker pillows of snow. Steer around these wind drifted features on slopes steeper than 35 degrees. 

Problemi valanghivi

  • Wind Slabs

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

    Wind-affected pockets of new snow is where you're most likely to trigger an avalanche on Monday. We received around a foot of snow in the last 36 hours, and in areas where wind deposited snow into deeper or heavier drifts it is possible for you to trigger an avalanche.  The higher you go the more wind will have affected the snowpack, and you can expect to see wind slabs much deeper than the snowfall amount that we just had, resulting in larger avalanches.

    Search for "pillows" on steep rollovers. Deposits may build up just below ridgelines, or in gullies.  Another common location where you might be able to find wind drifted pockets is around rocky outcroppings. If you travel near any of these areas, pay attention to the snow in front of you and under your feet, and notice whether deposits get deeper, or slightly stiffer.  That subtle change could be enough for you to trigger an avalanche. Conditions right now are deceiving because temperatures are relatively cool and the new snow is quite light and fluffy. Snow that avalanches will likely be very soft. Avoid slopes steeper than 35 degrees where you notice wind slabs formed.

    Keep in mind that this low density new snow could sluff, or dry loose avalanche, in steep, non wind-loaded areas. Be observant of any sluffs you might cause if you travel out onto steep terrain. This could be the case in all elevation bands. 

     

     

     

    You can trigger small slab avalanches in steep areas near and above treeline.  They could be larger where the wind distributed snow into deeper drifts at higher elevations. 

    Photo: Zack Mcgill

Avalanche Discussion

In the week leading up to this storm we had unusual wind events and surface hoar growth. In sheltered areas, most likely in the near treeline and possibly below treeline, surface hoar may lie preserved beneath the new snow layer. This means that triggering an avalanche could be easier than you thought it would be, or an avalanche could span further than expected if triggered. The new snow layer is shallow enough that you can dig with your hand down to the bottom of it, and see if snow breaks easily at the interface. You might be able to identify a layer of surface hoar between the new and older snow layers. It is not expected that surface hoar would have stayed preserved on south-facing aspects, where you're more likely to find a crust instead.  Although wind events occurred several days ago, there is a small chance you could trigger a deeper avalanche on an older, harder wind slab. This is especially the case if you make your way to higher elevations. 

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