Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

The warm and sunny weather will continue to influence the snowpack Sunday and drive wet avalanche concerns. After a chilly start to the day, expect the icy snow surface to slowly soften. Choose routes that limit the amount of time you need to spend underneath complex rocky terrain where avalanches could occur. 

Problemi valanghivi

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2

    This is a tricky avalanche problem that we’ve been dealing with for several weeks at Snoqualmie Pass. Unfortunately, this weekend’s very warm temperatures and sunshine aren’t helping. Water continues to move through the snowpack and reach the ground maintaining the possibility for large blocks of snow to fall off of very steep and rocky slopes. While you aren’t likely to trigger one of these avalanches, you sure don’t want to be under one if it decides to slide. Fortunately, crevasse-like glide cracks give you a great clue which slopes you should be concerned about. Choose routes that help limit the amount of time you need to spend under rocky terrain where you see glide cracks. Unlike some of our other wet avalanche problems, glide avalanches can occur at any point of the day or night and do not necessarily peak during the heat of the day.

    (1/12/2022) This is a great example of a slope you don't want to hang out underneath. Notice the steep rocky terrain with glide cracks, 

    Photo: Alpental Pro Patrol

  • Loose Wet

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

    Despite the date on the calendar, we’re in a very spring-time pattern. First thing in the morning, a solid overnight freeze should eliminate any loose wet concerns. That may change on some steep sunny slopes by the afternoon. Take time to step off your sled, skis, or board and see how deep your foot sinks into the snow. Monitoring how the surface is softening will help you anticipate loose wet avalanches. When you find more than 4” (ankle deep) of wet snow, start looking for more shaded and frozen terrain. You’re most likely to see wet snow on steep SE-SW slopes receiving direct sunshine. Shallow spots in the snowpack around rocks and cliffs can help accelerate this process. Because the snow surface is firm and the overnight freeze should be solid, this will limit the size of any loose slide. However, don’t let one of these small avalanches carry you into a terrain trap like over a cliff or into a deep gully.

    (1/21/2022)

    Small rollerballs with a very small loose wet avalanche on Friday near Source Lake in the Alpental Valley. You could see similar conditions Saturday. 

    Photo: Ian Nicholson

Avalanche Discussion

Normally with temperatures and sunshine like this, we’d be experiencing more elevated avalanche danger. However, the snowpack has been through a lot in the past two weeks and we have several things working in our favor. Long clear winter nights should allow the snow surface to freeze solid despite the warm temperatures. This will be particularly true at lower elevations where a temperature inversion helps to snow freeze. These shorter January days with the sun low in the sky will limit the number of slopes receiving direct sunshine. Most importantly, this warm-up comes as an extension of a nearly 2-week warm spell, where the snowpack saw rain and went through at least 2 wet avalanche cycles. As a result, the snowpack is very “spring-like.” A strong crust at the surface overlays large grain melt-forms, layers of moist rounds, and additional crusts. In short, this snowpack should handle the heat well. 

On Thursday night Snoqualmie received 3-5” of snow at mid and upper elevations. On more shaded aspects, you may still find this softer and drier snow sitting on a firm crust. At the highest elevations, recent winds might have turned this small storm into a few isolated winds slabs, particularly in more exposed terrain. If you head for the tops of the higher peaks around the Pass keep your eye out for wind drifted snow, especially before you commit to high consequence terrain.

Regioni coperte