Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

The likelihood of very large and destructive wet avalanches is ratcheting down, but they will remain possible on Thursday. Avalanches could be 3-4ft deep, and run on old crust layers and/or the ground. Although the danger is Moderate, its a scary one, so stick to lower angled slopes until the snowpack refreezes.

Lawinenprobleme

  • Wet Slabs

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

    A prolonged period of warm and wet weather, combined with a deeply buried weak layer have created unique conditions for scary and deep wet slab avalanches. These are running on old faceted and crust layers from December, and/or on the ground. What does this mean? It means slides may fracture across terrain features, and carry most of the seasons snowpack with it. Slides may be 3-4ft deep, and could be powerful enough to take out trees. 

    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. Even if avoiding travel on steep slopes, pay attention to what is above you.  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

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

    Water is running through and underneath the snowpack. Glide (slipping of the entire snowpack) activity has increased over the past 48 hours, and may continue on Thursday. Typically glide slabs 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 are finally going to begin cooling, and the rain might let up a bit on Thursday. We're still coming out of a very wam and wet period, and the snowpack probably won't begin to refreeze until Thursday night. Water has been percolating through the snowpack, and may have gone all the way through in most areas besides the highest elevations. Snow is beginning to sag away from rocks and cliffs, and glide cracks are opening up. 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.  

An initial period of avalanche activity seemed to happen at the end of last week and over the weekend.  Many wet loose and slab avalanches up to D2 were reported. Avalanche control work at Stevens Pass Ski Area over the weekend produced a couple of avalanches that broke into older, deeper layers that have been lingering in the snowpack since late December. Regionally, very large slides have occurred on a similar old weak layer at Mission Ridge on Wednesday and Crystal Mountain a week ago. This crust/facet complex is now 3-4 feet below the surface in much of the zone. Last week, observers reported sudden and propagating test results on this weak layer.

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

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