Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Newly formed wind slabs may place additional stress on buried weak snow on Wednesday. In areas that are not heavily wind-loaded, there is still a risk of triggering an avalanche large enough to bury you. Avoid steep slopes with deep, wind-loaded snow, as well as complex, rocky terrain.

Problemi valanghivi

  • Persistent Slabs

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

    Two different avalanche problems will overlap on Wednesday. Wind slab avalanches will be more obvious out there, but persistent slabs are the scary ones to plan for.

    Persistent slab avalanches will still be possible on Wednesday, especially at upper elevations in wind-loaded and rocky terrain. These slabs are most likely to fail on the 2/13 or 2/7 interfaces, which are close to 2 feet beneath the surface. Unfortunately, these types of avalanches are very difficult to predict when and where they will happen. What we do know is that weak layers exist in the upper snowpack, and parties continue to report unstable activity. You're most likely to trigger one of these avalanches in areas of slightly shallower new snow, rocky slopes, or areas of deeper wind-drifted snow. 

    Your standard small test slopes won't work well with identifying this problem, and not seeing avalanche activity doesn't mean a slope won't release. To mitigate your risk, choose the proper terrain. Steer clear of ridgelines, cliff bands, and rocky terrain where a new wind slab could step down to weak layers below. As always, long shooting cracks, audible collapsing underfoot, and recent avalanche activity are all good indicators of an unstable snowpack, but they can also occur without these signs.

    (2/24/2026)

    A natural, very large (D3) persistent slab that released over 800 feet wide in the West South zone. This avalanche failed on the 2/13 buried surface hoar.

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

This is a tricky time to be traveling in the backcountry around Snoqualmie Pass. Persistent slabs are notoriously difficult to predict and can vary widely from slope to slope. 

On Tuesday, an NWAC forecaster and professional observer traveled to Snow Lake Divide, where they identified both the 2/7 and 2/13 interfaces. Both layers continued to show signs of weakness and the potential to produce avalanches, though triggering an avalanche from the surface was difficult. In contrast, another party near Red Mountain reported much more sensitive results, with propagation in pit tests (ECTP17 and ECTP14).

This variability is what makes persistent slabs so challenging to manage. There often isn’t obvious, in-your-face feedback, and results can differ significantly from one area to the next. Keep it simple; These weak layers are still present in the upper snowpack and can produce avalanches. Continue to move methodically, minimize exposure to steep terrain, and use appropriate travel techniques on consequential slopes.

The past 24 hours have provided a light break in the wind around the Pass, but that’s expected to change on Wednesday. Increasing wind speeds will likely form fresh drifts and wind slabs on leeward slopes. Watch out for newly deposited, wind-drifted snow near ridgelines, cliff bands, and other exposed, steep terrain facing downwind. If triggered, these wind slabs could step down into buried weak layers, creating a larger avalanche.

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