Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

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2 · Moderato
Limite del bosco
2 · Moderato
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

You could find small shallow slabs on the lee sides of ridgelines and exposed features Sunday. Steer around smooth pillow-like drifts on any steep slope above cliffs, in confined gullies, or around rocks where even a small avalanche may harm you.

Problemi valanghivi

  • Wind Slabs

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

    At mid and upper elevations strong winds may combine with recent snow to form small shallow wind slabs. On Saturday, the winds were already transporting the snow into thin drifts in the Alpental Valley. We expect this to continue into Sunday. While most of these slabs shouldn’t be large enough to harm you, use caution if you travel on to higher consequence slopes. Even a small wind slab can kill you in confined or cliffy terrain where you might not be able to avoid the avalanche hazard. Look for wind stiffened and textured snow surfaces to help clue you in to where these wind slabs may exist. Steer around wind-loaded features especially above terrain traps that can magnify the consequences of any avalanche. 

    (1/9/2021) Wind textured snow surfaces provide great clues that wind slabs may exist nearby. Chair Peak 5300'. Photo: Ian Nicholson

Avalanche Discussion

You may find a few inches of new snow around the Pass by Sunday morning. This new snow on its own shouldn’t create much of a hazard. It will need to combine with Friday's snow and the wind to pose a threat. 

While the avalanche hazard should stay confined to the upper few inches of the snowpack, don’t forget a weeklong storm cycle very recently deposited more than 8’ of snow (w/ 11.5" water) at 4000' around the Pass. Plenty of uncertainty remains around the large volume of snow that fell last week, particularly at upper elevations. Observations from several avalanche classes at Snoqualmie Pass Saturday found the upper snowpack generally right-side-up and gaining strength. However, two notable snowpack markers continue to stay on our minds. You may find a subtle storm snow interface (1/5) about a foot (30cm) below the surface. Many snowpack tests continue to fail at this interface, with some producing planar results. If you dig deeper, a crust was formed and buried on all aspects up to at least 5500’ on New Years Day. You may see this thin  1/1 crust about 3-4.5 (90-145cm) below the snow surface. We suspect several large crowns still visible on the higher peaks failed at or near this layer. If you have observations about these layers or any avalanches please take the time to submit an observation and let us know what you find. 

Despite all the recent snow and deep snowpack, many creeks at lower elevations remain open. Give your self plenty of time to find safe crossings around these non-avalanche hazards. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regioni coperte