Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Fri
Alta quota
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 may find new wind slabs in some unusual locations like westerly facing slopes, along the sides of gullies, and well below ridgeline. Travel around these smooth pillow-like drifts on any steep slope.

Problemi valanghivi

  • Wind Slabs

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

    Wednesday’s strong easterly winds likely formed small new wind slabs on slopes the typically get stripped during storms. Watch for smooth pillow-like surfaces that indicate shallow wind deposits. You are most likely to see these on westerly aspects, well below ridgeline, and cross-loaded along the sides of mid-slope features.  On N-E aspects, much older, larger, and harder to trigger wind slabs could still linger from Monday’s storm. If you feel firm hollow-sounding snow, steer around nearby areas greater than 35 degrees. While these older wind slabs should be hard to trigger, they could produce larger avalanches that break above you.

    (12/2/2020) Large plumes of windblown snow were great clues to indicate where the new wind slabs were forming Wednesday. Photo: Porter McMichaels, CMSP

Avalanche Discussion

Snoqualmie Pass escaped much of the hot weather Wednesday due to cold easterly winds. Look for the cool east breeze to decrease Thursday before shifting westerly overnight. This should create a shallow inversion with colder temperatures near Pass level. As a result, you’re most likely to encounter warm weather at higher elevations and in areas west of the Pass. These warm temperatures could combine with sunshine to allow for a few isolated loose wet avalanches. If you see new rollerballs or find the snow surfaces becoming wet and sticky, seek out more shaded slopes. Increasing clouds in the afternoon should help keep the loose wet concerns confined to a few rocky slopes. 

The snowpack around Snoqualmie Pass is generally strong. Any avalanche activity should occur within the recent snow or at the newest interface (11/30). Prior to this week’s storm, surface hoar was reported by avalanche professionals at Hyak. Others observed the same weak snow near the Teanaway, Chiwaukums (E Central), Crystal, Tattoosh, and White Pass areas. So far, no avalanches have been reported on this layer. If you dig on a shaded and sheltered slope, particularly in the eastern part of the zone, let us know what you see by submitting a public observation. 

At lower elevations, early season conditions still exist with numerous small trees, logs, and open creeks that could ruin your day. Allow extra time to navigate these obstacles.

Regioni coperte