Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Unusual loading patterns may create Wind Slabs on a variety of aspects on Monday. Textured surfaces or actively blowing snow can help you identify the areas you want to avoid. Uncertainty around recent very large avalanches should be in the forefront of your mind if you plan to head for alpine terrain.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Cool easterly winds are expected to continue loading features and ridgelines at upper elevations on Monday. Wind Slabs formed by east winds are often on the opposite side of the ridge from where you are used to finding them. Additionally, there can be more cross-loading or mid-slope loading than our typical loading patterns. You can still look for textured snow surfaces or actively blowing snow to help you identify wind-loaded terrain to avoid. Firm snow that feels hollow and breaks off in blocks is an easy indication of wind-loaded terrain and you should avoid similar snow on steeper features. A wind direction change is expected during the daylight hours, so staying vigilant for freshly building slabs on all aspects will be a necessity. 

    (1/9/2022)

    East winds easily transported snow around Snoqualmie Pass on Sunday (1/9), building fresh Wind Slabs in the process.

    Photo: Erik Olson

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    A competition between warm air and cool easterly flow will determine if rain is able to fall at lower elevations and drive a Wet Loose issue on Monday. If you find that the warm air has won and rain is falling on snow, be prepared for some Wet Loose avalanches. These avalanches often start at a point before entraining snow and fanning out as they move downhill. You can avoid this hazard by avoiding steep slopes and keeping aware of the terrain above you. Warm temperatures and rain could also help blocks of snow and ice to fall from rock ledges, trees, or structures such as rooftops. The longer we have elevated freezing levels, the more likely cornice failures and glide avalanches will be.

    (1/9/2022)

    A natural Glide avalanche occurred within the Alpental Ski Resort on the night of 1/7. This slide contained the entire season's snowpack as evident by the exposed rock.

    Photo: Alpental Pro Patrol

Avalanche Discussion

There have been some very large avalanches recently at Snoqualmie Pass. WSDOT’s avalanche crew and Alpental both reported widespread natural activity during this past week’s storm up to size D3, which came as no surprise. Alpental Pro Patrol was also able to trigger a D3 slide with explosives during their mitigation work. The surprise came on the West Face of Kendall Mountain where an avalanche that is easily a size D4 has been reported. The slide ran approximately 1500 vertical feet, clearing out a new area of the forest as it descended. We do not know what layer this slide failed on or have an estimated crown depth. 

If you are going to venture to alpine terrain, you need to know that very large slides may still be possible given a large enough trigger. These triggers are out there, it’s just a matter of if they fail and if they fail in the wrong place. Cornices have grown large and may still be fresh. There have been recent Glide avalanches at Alpental involving the entire winter’s snowpack. A general warming trend may only enhance the likelihood of one of these potentially large triggers failing. Even a Wind Slab like we expect to see on Monday could step down into deeper layers of the snowpack given the right slope. Take this knowledge with you and talk to your partners about the added risk associated with your selected terrain. If you happen to be caught in one of these slides, it would most certainly be unsurvivable. 

If you are out and about and notice recent avalanche crowns or debris piles, please take a picture and share it with us as we try to track and document this cycle. The evidence of these avalanches may be hidden by some fresh snow sitting atop them, but we’d appreciate a picture of anything you suspect as an avalanche. Other useful information to accompany a picture is the location of the avalanche, along with aspect and elevation if possible. You can submit this information on our observation platform either privately or publicly. 

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