Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Strong winds drifted the recent snow into thick and reactive slabs, making human-triggered avalanches likely. Look for signs of wind effect like textured surfaces and pillowy deposits and avoid steep open slopes where you see them. Sunshine and warming will add to the hazard so give a wide berth to steep sunlit slopes, whether they are wind-loaded or not. 

Problemi valanghivi

  • Wind Slabs

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

    Up to 20" of fresh snow was hammered by the wind on Tuesday, resulting in widespread hard and soft slab avalanches. Wind-affected snow will be found at all elevation bands and below tree line on Wednesday. Look for signs of wind effect in the usual locations like below sharp ridges and cliffs and at the tops and sidewalls of gullies, but also in treed terrain and below mid-slope rollovers. Cracking and collapsing are obvious signs of instability and hand pits, uptrack tests, and small test slopes can all be used to help gauge slab behavior. Keep in mind, however, that it can be hard to find a representative test slope that has the same conditions as the slope you are eying and you may not see any obvious red flags. Hard slabs are especially problematic as they can let you well out onto the slope before releasing, can break above you, and propagate widely around terrain features. 

    The best bet on Wednesday is to avoid steep slopes wherever you see signs of wind-blown snow. This approach will also steer you towards more enjoyable riding conditions.   

    (1/1/2025)

    A wind slab avalanche triggered earlier in the season in confined terrain. Expect simlar avalanches, or bigger on Wednesday.

     Photo: Ryan Stoddard

  • Loose Wet

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

    New snow will see the sun for the first time on Wednesday. Look for fresh wet avalanches, rollerballs, pinwheels, and sinking in past your boot tops into moist snow. If you see any of these signs, it's time to switch to a shady slope. Be aware of what you are below as snow may shed off rocky faces before the surface you are on shows signs of moistening. With so much fresh snow on the surface, some avalanches could gouge deeply and run far. Wet loose avalanches could also act as a trigger for deeper slab avalanches.

    Glide cracks and avalanches were reported on Monday. As water is still percolating its way down through the snowpack, we can't rule these out. Don't linger below any open glide cracks. 

    (1/5/2025)

    Natural wet loose avalanche activity in the Snoqualmie backcountry.  Expect wet loose avalanches on steep and sunlit slopes on Wednesday.

    Photo: Jenny Kaltunas

Avalanche Discussion

Since this cycle began, a whopping 8.47" of precipitation has fallen. While much fell as rain, the final act brought a much-needed refresh of snow above about 4000ft. 12-20" (2.02" SWE) fell from Monday through Tuesday and the winds ripped. It was a white out so observations are limited, but Summit at Snoqualmie Pro Patrol noted widespread and reactive slabs in the morning, trending more stubborn throughout the day, with wet loose avalanches running below about 3500ft where rain mixed with snow. While we expect any storm slabs to have mostly settled out, they could pose an issue on steep and unsupported slopes. Between the warm temperatures and the hammering winds, the snow surface will be a mixed bag on Wednesday.

It's almost March and the sun is strong! While some slabs may start the day as stubborn, we are uncertain as to how they might react to warming. On top of that, the snowpack has been hammered by liquid water and snow and it hasn't fully adjusted to the load, nor has all of the water frozen or finished its journey through the snowpack. Though the 1/10 is mostly out of sight and out of mind, until the snowpack is fully locked up above it, we can't totally write it off.

We'd love help documenting avalanches from last cycle. If you are out and about, please shoot some photos and submit an observation!

Regioni coperte