Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The biggest hazard you face could come from the snow shedding off of very steep and rocky slopes. Continued warm weather may only make this issue worse. So, choose routes that minimize the time you spend underneath these very specific large craggy features.

Problemi valanghivi

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3

    It’s easy to see “unlikely” and downplay this avalanche problem. However, it continues to top the list of concerns for most avalanche professionals traveling around Snoqualmie Pass. As the snowpack creeps and glides under the stress of recent rain and ongoing warm temperatures, some of these slopes could eventually fail. If you happen to be unlucky enough to be underneath it when it slides, it would likely be fatal. Unfortunately, these types of avalanches can occur days after the rain stops, making them incredibly challenging to predict. However, glide avalanches give us clues to their possible locations. Look for crevasse-like cracks, especially in very steep and rocky terrain, to indicate areas you may want to avoid. Choose routes that help limit the amount of time you need to spend under these features or avoid them all together. 

    Glide avalanches aren’t the only snow that wants to fall down due to the prolonged warm weather. Cornices and even blocks of snow clinging to rocks could give way due to the ongoing above freezing temperatures. Just like glide avalanches, the key is to pay attention to the slopes above you, look for these hazards, and then minimize any time you spend underneath them.

    (1/13/2022)

    Glide cracks abound on many steep slopes at Snoqualmie Pass. These crevasse-like features indicate the settling and gliding motion of the snowpack. Sometimes, these same slopes give way without warning and produce glide avalanches. 

    Photo: Robin Pendry

  • Loose Wet

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

    The chance for loose wet avalanches Saturday depends on two factors: how strong the snow freezes overnight, and how much sunshine you experience on Saturday. One of your best tools to measure this potential is your feet. Step off your sled, out of your skis, or off your board to see how deep your boot skinks into the snow. If you find the surface is punchy or getting wet, it’s time to seek out lower angled or more frozen slopes to continue your day. You may find that the hazard changes greatly by aspect and elevation. Look for wet snow to develop first SE-SW aspects that receive direct sun and at mid-elevations where overnight temperatures may remain substantially warmer. New rollerballs and even small point release slides are also clear signs of unstable wet snow. While most of these avalanches should remain small, in bigger terrain, they could gather additional snow to grow large enough to bury you.

    (1/13/2022)

    Nope, this isn't a snowpit. The wet surface snow is weak and unsupportable. If you find the surface crust breaking down, anticipate an increase in the wet potential for wet avalanches. 

    Photo: Andy Harrington

Avalanche Discussion

On Friday, observations found a stout and generally supportable snow surface around the Pass. At lower elevations, fog and low clouds kept conditions cool and made the surface icy. Above the clouds, the surface softened in the sunshine but did not fully break down. No new avalanches were reported. The upper snowpack consists of alternating layers of weak wet snow, thin crusts, and strong rounded grains. While some weaknesses can be found, they do not appear to be widespread across the landscape. 

Recent avalanche cycles (Jan 6-7, and 11-12) give us confidence the snowpack has been well tested. However, the ongoing warm temperatures provide a significant source of uncertainty and continue to maintain the danger. Most weather stations at the Pass have not dipped below freezing since early Tuesday morning (3-4 days ago). Keep this information on your mind and discuss it with your team if your plans could take you into bigger and more high consequence alpine terrain. 

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