Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

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

Enjoy the dreamy white Christmas, but recognize that you could trigger avalanches of various shapes and sizes. Large wind slabs can be found on open, wind-exposed slopes. Loose avalanches may be easy to initiate in sheltered areas. Don't let the avalanche grinch ruin your holiday by letting your guard down on steep slopes.

Lawinenprobleme

  • Wind Slabs

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

    You'll find a couple of generations of wind slabs as you gain elevation. Thursday into Thursday night was the main wind event, and created some very thick slabs in many areas. These could be tricky, as wind slabs sometimes are. Slabs could be fresh, or they could be disguised underneath recent snow that fell without wind. Look and feel for thicker drifts, textured surfaces, and shooting cracks. You are most likely to trigger one on steep slopes near and above treeline in exposed locations, such as the leeward sides of ridges and gully edges. Avalanches could be larger at upper elevations, where there is more snow and drifts are deep.

    Avoid suspect-looking areas and likely starting zones such as convex rolls and pillowed snow on steep slopes. Stay off of steep slopes altogether if you find evidence of instability such as shooting cracks or the snow feels hollow or punchy.

     

    (12/23/2021)

    Wind slab on a small slope. E aspect at 5,400ft.

    Photo: Matt Primomo

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–1.5

    If you enter a steep slope, expect that you could trigger an avalanche. Sluffs and soft storm slabs have been easily triggered outside of wind affected terrain the past couple of days, and should continue on Saturday. You are most likely to trigger a sluff on very steep or unsupported features. Use test slopes to evaluate how the new snow is bonding as the day progresses. If you choose to enter steep slopes even outside of wind affected areas, travel defensively, as these slides could gain momentum and run far. If a slab fractures out, the slide could be much wider and larger than anticipated. 

    (12/23/2021)

    Loose dry avalanches have been easy to trigger on steep slopes.

    Photo: Joe Dellaporta

Avalanche Discussion

Happy Holidays! We've been in a storm cycle since the Solstice, and the snow just keeps adding up. A relative lull in the stormy conditions occurred for part of Friday, but as I write this yet another storm is rolling in, and it's snowing heavily on the pass. Storm totals since the 21st are around 24" and counting. Temperatures will continue to drop, and winds could be strong enough to move snow near ridgelines. On Thursday winds were very strong and created thick wind slabs in many areas. 

On Friday, avalanche control teams at SPMR and WSDOT triggered numerous avalanches, both soft slab and loose dry slides in the new snow. Slides were mainly small, with some up to D1.5. Other observers found sluffs were running easily in the upper 6" of snow on steep slopes and with tree bombs. On Thursday, slides were larger at higher elevations where wind created thicker slabs. The snow is getting deep, and it's time to stay away from tree wells and consider the dangers associated with deep snow immersion safety. Trees have also been toppling over under the weight of the heavy snow. Keep your partners nearby in these conditions.

The snowpack is gaining depth and exhibits a sound structure with stronger snow near the base, and lower density snow near the surface. A number of crusts may be found in the mid and lower snowpack. They aren't expected to be problematic for avalanches at this time but are worth monitoring.

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