Lawinenlagebericht

East Slopes Central

Northwest Avalanche Center
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Lawinengefahr

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

You could trigger avalanches in freshly wind-drifted snow or very large avalanches that run on deeply buried weak layers. Smaller avalanches could step down to deeper layers and become very large, breaking widely across terrain features. Stick to low-angle slopes in simple terrain to avoid triggering a dangerous avalanche. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–2.5

    Blustery conditions will return to our mountains and quickly form fresh wind slabs on lee aspects. Identify wind-loaded features with visual clues like actively blowing snow, cornice formations, and textured surfaces. Avoid steep slopes where you find these stiff, wind-drifted slabs. With 2-3ft of fresh snow in the last 48 hours, these avalanches could easily be large enough to bury, injure, or kill a person. These avalanches could also step down to more deeply buried weak layers and become very large, propagating across terrain features. Look for signs of instability, such as collapsing, cracks that shoot away from you, and recent avalanches. These are all indications that you are likely to trigger an avalanche. At lower elevations with a thinner snowpack, avalanches might be smaller, but they would carry high consequences if you are dragged through terrain still riddled with rocks, stumps, creeks, and other terrain traps.

    (1/7/2024)

    In this photo, you can see wind drifting snow over the ridge. This is a sign of wind slabs on the slopes below. 

    Photo: Katie Warren

  • Persistent Slabs

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

    You could trigger a very large persistent slab avalanche on various layers now buried 2-4 feet deep. These avalanches can propagate widely around terrain features, and you may be able to trigger them from adjacent lower-angle slopes. The best way to manage this avalanche problem is to simply avoid steep open terrain. Instead, seek out low-angle, simple terrain. Before this storm, there were numerous close calls with avalanches on these persistent weak layers. Post-storm, these same layers are buried much deeper and continue to produce avalanches. Mission Ridge Ski Patrol triggered multiple avalanches that failed on weak, faceted snow over the Solstice Crust, and a backcountry traveler near Lake Wenatchee remotely triggered a small avalanche on a steep convexity on this same layer. Buried surface hoar (1/2) was responsible for two other human-triggered avalanches before this storm. We have yet to hear about more recent avalanches on this layer, but it could still be an issue. With both layers potentially lurking below the surface, extra caution and wide safety margins in your travel plans are warranted. 

    (1/10/2024)

    Backcountry travelers near Lake Wenatchee remotely triggered this avalanche from a low angle adjacent slope. This avalanche ran on weak, facted snow over the Solstice Crust.

    Photo: Pat Riffie

Avalanche Discussion

We may get another dusting of snow on Thursday, but the main event will be increasing winds. It will probably feel like a stormy day in the mountains, and avalanches could become more likely as winds increase in the afternoon. Southern slopes warmed in the sun on Wednesday and now have a thin, breakable crust on the surface. 

I got out into the Salmon La Sac area on Wednesday to take stock of the new landscape after the impressive storm early in the week. There is just over 2ft of new snow down to the snowpark. Steep test slopes only produced moderate cracking beneath our skis within the recent storm snow. At 4600ft, I found around 70cm of new snow with a thin melt-freeze crust from a brief warmup midstorm buried 45cm down. This new melt-freeze crust showed potential for propagation in a snowpack test. Weak snow beneath the Solstice Crust also showed propagation in these test results. The extreme winds drifted snow well down into forested areas, and we found wind-pressed surfaces with little ski penetration in open terrain. In sheltered terrain, it was deep!! Snowmobiles got stuck quickly, and stepping off put you waist-deep into the snow.

Lower elevations have significantly better coverage after Tuesday's storm, but the coverage is still below average. These elevations may not quite meet the threshold for large avalanches. However, you could still trigger a smaller avalanche with serious consequences from hitting exposed hazards like rocks, stumps, or downed trees. 

If you get out, let us know what you see by submitting a public observation!

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