Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Large and destructive wet avalanches that run on old weak layers near the ground will remain possible until the snowpack has a chance to freeze. Glide cracks are also opening up, and present an unusual hazard. To avoid these hazards, use lower angled and well supported slopes away from larger terrain features.

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    We're still easing our way out of a prolonged period of warm and wet weather. Deeply buried weak layers from earlier in December have proven themselves responsible for very large and destructive wet slabs over the past handful of days. Slides may be 3-4ft deep, and could be powerful enough to take out trees. In some cases, they gouge down to the ground and carry all of the seasons snowpack with it. 

    Although the likelihood is ratcheting down, it's recommended to stick to lower angle and well supported slopes until the snowpack has a chance to refreeze. Higher elevation terrain may have a thin crust on Friday. If you find the crust is supportable, then the chances of triggering a slide drop significantly. Stay out from under cornices that could fall and trigger a large avalanche on the slope below.

    (1/30/2024)

    Very large wet slab debris took some trees out at SPMR.

    Photo: SPMR

  • Glide Cracks

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

    Glide (slipping of the entire snowpack) activity has been occurring, and glide avalanches have been observed on a regional scale over the past 3 days. Glide slabs typically run on smooth bedsurfaces, like rocks and grass. These slides could entrain more snow on steep slopes if they run. Large, complex terrain features can funnel debris into deeper areas into gullies. Stay away from these types of runout zones while its raining or if you see glide cracks. 

    (1/30/2024)

    A glide avalanche in Snoqualmie zone. This frequent flier is a good indicator that water is still making its way through the snowpack. We're not done with wet avalanches.

    [E 3900' WS-N-R2-D2-G]

    Photo: Alpental Pro Patrol

Avalanche Discussion

Temperatures have slowly begun to cool, and the rain is letting up. We're still coming out of a very wam and wet period, and the snowpack probably won't get a solid freeze until Friday night. Water has been percolating through the snowpack, and may have gone all the way through in many areas besides the highest elevations. Snow is beginning to sag away from rocks and cliffs, and glide cracks are opening up.

On Thursday, we visited a profile study site near Skyline lake and found just about 6ft of snow on the ground. The Solstice Crust was 3.5ft down, and still produced sudden collapse failures with a deep tap test, and propagating test results with a propagation saw test. So, although this layer is rounding, and the snowpack is adjusting to the rain, it remains possible for avalanches to occur. On Tuesday, Stevens Pass Mountain Resort reported a handful of very large avalanches with control work, and at least one D3 that took out trees. Slides stepped down to old weak layers, and one path even slid twice (hangfire took out the bedsurface of a slide that was triggered earlier in the day). A very large natural avalanche (D3) was observed in the Chiwaukum Range, along with a number of smaller slides that ran on the ground (see photo). Some of these slides may have taken out trees, and left nasty streaks of dirt in their wake.  

If you make it out, please share what you found with an observation.

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