Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

You may be able to ride on some slopes without triggering an avalanche, but on others you might trigger 1.5-2.5ft deep slabs. Enjoy the beautiful day and excellent powder, but steer away from slopes of increased consequences if you find the sun is creating more cohesive slabs, thicker slabs from wind, or any signs of instability like shooting cracks or whumphing. 

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    A number of slab avalanches were observed either naturally or rider triggered on Saturday, and although conditions may settle out some, chances should remain to trigger them on Sunday. Most slides will likely run on or just above a recent crust, and could be 14-20" deep. However,  slides have the potential to step down to any number of weaker snow layers, up to 3ft deep on older, sometimes slick crusts. With multiple potential weak layers, it'll be prudent to look for more supported and lower angle slopes to ride on.

    Slabs could be thicker and larger on wind affected slopes at upper elevations. Here, they may also be easier to trigger.  Look for signs of instability, including long shooting cracks, whumphing collapses, and recent avalanches. The sun may also inrease cohesiveness during the daytime. Terrain features such as steep convex rolls near ridgelines may be most likely areas to trigger a slide, but even steep, mid slope features should be viewed as suspicious. Use safe travel techniques, and limit the amount of people exposed. 

    Skier triggered slab about 18" deep on a N facing slope of Valhalla Peak.

Avalanche Discussion

The pass picked up 14-18" of new snow, and a little more might come in by Sunday morning. Winds blew strong in some areas, and created more cohesive slabs. Multiple natural and human triggered slides were reported on Saturday. A skier was caught and carried a short ways in a 1.5ft deep slide on the N side of Valhalla Peak. Luckily no burial or injuries were reported. They reported hearing a whumph when it broke, and it ran on a soft crust (potentially the 12/30 interface). Control work at SPMR produced a handful of large slab avalanches, and many smaller ones. The D2's were in areas where wind created thicker slabs. These all ran on the most recent crust. Another observer reported a few small naturals on Jove Peak. One of these is an interesting, mid slope slide from a NE aspect at 5,600ft.

New snow may begin to settle out some on Sunday, but we have uncertainty with what the sun may do. The sun may create more cohesive snow and actually increase instability during the day. With direct sun also comes some potential for rollerballs and small loose wet avalanches.  weak layers are here with us through the weekend and are likely to produce avalanches well into the week as more storms keeping adding up. 

Over the past week, observers have been finding sudden and propagating failures with crust, and facet/surface hoar layers that date all the way back to the Solstice. These layers can be found 1-3ft down beneath the storm snow. At mid and upper elevations you may find a slick, translucent crust with facets and/or surface hoar above or within. These layers are widespread around the region, and are likely to play a role with larger avalanches as more snow adds up.

Travel conditions and coverage are still thin, but improving by the day. Continue to beware of hitting exposed rocks, stumps, and creek openings, especially at lower elevations. You can contribute to the forecast! Let us know what you found by submitting an observation HERE. 

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