Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Fluctuating freezing levels, heavy precipitation, and strong winds will create a dynamic day in the mountains. While no single avalanche problem is likely, their overlapping nature could lead to dangerous conditions as the weather shifts. Avoid steep open slopes where larger slides could occur.

Problemi valanghivi

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2

    We'll be back into heavy rain Saturday night into Sunday morning. The upper snowpack has been wet for a few days now and should be well-suited to handle additional water. We've been talking about wet loose slides in recent days. Well, those are likely played out at this point, but the snow surface remains wet and weak. You should now turn your focus to larger, more difficult-to-predict wet slides.

    Call them glides, cornice failures, wet slabs, or even just wet snow falling off rocky ledges - it doesn't really matter what title you give them. What we're talking about is the lingering instability of the upper snowpack due to significant rain and warm temperatures. 

    Any triggered wet slide will be heavy and hard to maneuver away from if you get caught. So be leery of steep slopes where they can get a head of steam and barrel far downhill.

    (3/7/2026)

    Heavy, wet avalanche debris from a glide avalanche at Alpental on Friday night. If you were to get caught up in one of these slides, you'd have a very difficult time escaping, even though it may be slow-moving.

    Photo: Summit at Snoqualmie Pro Patrol

  • Wind Slabs

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

    As temperatures slowly cool throughout the day, snow should start to accumulate at upper elevations. With strong winds accompanying this storm, it's not out of the question that a batch of small wind slabs develop by the end of the day. 

    We expect the new snow to bond well to the warm and wet surface, but if drifts form near rocky features or on the leeward side of ridgelines, you may find some instability. Don't get tripped up by one of these small slides in consequential terrain.

    (2/20/2026)

    Visual clues can help you identify wind-loaded features to steer around.

    Photo: Dallas Glass

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Sunday may be the final day to worry about our persistent slab problem, but there's a chance this problem could go out with a bang.

    If water reaches the 2/13 or 2/7 interfaces, these weak layers could fail, similar to a wet slab. Or another avalanche, like the ones mentioned above, could stress these weak layers, resulting in a secondary slide. 

    Give steep, open slopes a wide berth where these slides are more likely to be very large and dangerous.

    (3/3/2026)

    A snow profile on a sunny aspect highlighting the main persistent weak layer of concern. 

    Photo: Dallas Glass

Avalanche Discussion

We're in the midst of a warm and wet weekend at Snoqualmie Pass. Rain has fallen to ridgecrest throughout the zone and will again on Saturday night. A saturated upper snowpack resulted in a large glide release at Alpental, according to the Summit at Snoqualmie Pro Patrol. Further up the Alpental Valley, backcountry travelers reported wet avalanche debris near Source Lake that was flowing out of the Bryant Peak Couloir. It is unknown if this was a slab, glide, loose, or cornice, but it likely doesn't matter. The take-home point is that the snow surface has been getting wet, weak, and producing avalanche activity. It is almost impossible to predict wet avalanche timing, so use good travel techniques to avoid steep open slopes where these slides could be large and dangerous. 

The good news is that on Sunday, we're expected to cool down and precipitation will return to snow. The timing is a bit up in the air, but look for snow levels to slowly fall throughout the morning. Just because it turns to snow doesn't mean wet avalanche potential will end on a dime, however. It will take some time for the surface to firm up, providing greater stability and helping to put our persistent weak layers to bed for the time being. The moderate to strong winds should help this process accelerate, but we are moving toward spring and daylight saving time, so be patient.

Coverage in the mountains remains thin. New snow will help, but may only mask problems that were previously easy to identify. Holes, creeks, bushes, and rocks are just some of the natural hazards that have plagued us all season and will continue to do so.

Regioni coperte