Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
Open full map
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Kernpunkte

The main atmospheric river event has ended, but we're not out of the storm track. Don't overlook the amount of liquid water soaking our snowpack. Unpredictable wet avalanches can still occur naturally, so consider avoiding avalanche terrain altogether until this stormy period wraps up.

Lawinenprobleme

  • Wet Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    There is a lot of water in our snowpack right now, and the rain is still coming. Wet avalanches are notoriously difficult to predict and can even occur long after the rain has stopped. You could encounter various wet problems in the mountains, including loose, slab, glide, and we'll even throw in cornice. Just because a slope has already slid in the past few days doesn't mean it can't again. Although the period for widespread natural activity may have passed, these slides can still occur naturally without warning. In some instances, they may grow very large and run toward valley bottoms or openings in the trees - especially if water has recently reached our persistent weak layers. No matter the size or the timing, your best bet is to avoid avalanche terrain (anywhere a slide can start, run, or stop) for a few more days until the rain ends and our snowpack adjusts.

    (2/23/2025)

    A shallow slab, glide cracks, and other wet avalanche debris. Our snowpack took a real beating during this atmospheric river.

    Photo: Josh Lipkowitz

  • Wind Slabs

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

    The winds are going to be ripping during these subsequent storm waves! The question mark becomes - how much snow is available for transport? With decreasing freezing levels, there should be enough new snow that these fierce winds may form shallow slabs on leeward slopes. If you journey to snowier elevations, look for wind slabs near ridgelines, the base of cliffs, or convex features. They should be pretty easy to spot. They'll be the large piles of new white snow. Once you spot them, steer around them so you don't trigger a small slide.

    (12/16/2024)

    A shallow wind slab in a confined chute. This slide failed as snow fell after a rain event earlier this season. Similar slabs could form on Monday above the rain/snow line.

Avalanche Discussion

Take a bow, Snoqualmie Pass. You recorded the most water in the NWAC network during this atmospheric river event. As of Sunday evening, we're approaching 5" of water since it started raining on Friday afternoon. And that's with a nice lull in the middle of the day on Saturday! It should come as no surprise that avalanches followed as this much rain fell on a weak and dry snowpack. We're still gathering information, but the little data we do have indicates widespread natural activity occurred, with both loose and slabs spotted during periods of limited visibility on Sunday. Numerous glide cracks were also reported. We have very few observations from upper elevations due to the ferocity of the storm.

The peak of the storm and natural avalanche activity has likely passed. That doesn't mean we're all wrapped up and ready to return to normal. A series of fast-hitting wet storms will continue to deliver rain down low, but hopefully, a return to snow up high. Above the rain/snow line, significant winds, decreasing freezing levels, and snowfall should help stabilize our saturated snowpack from the top down, but don't write off those wet problems quite yet. There may still be a few whoppers out there ready to come down and run toward valley bottoms or common travel routes. With so much uncertainty about what has happened, how much water is still in the snowpack, and how it will react to more load over these next few storms, you should continue to be very cautious in the mountains. Consider not going at all or being very stringent with your terrain selection.   

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