Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

On Monday, more precipitation than anticipated fell in the East Central with sustained winds, with more snow expected overnight. Dangerous avalanche conditions exist at upper elevations, where you can trigger large avalanches in deep drifts of snow. Avalanches at lower elevations may be smaller, but it will still be important to steer around steep ridgeline terrain with pillow-like drifts of snow. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    On Monday, sustained rain and snow fell on the East Central zone, particularly in the Icicle Creek area. While this storm largely missed the Cascade Passes, it turned the hose on the eastern slopes. With steady winds in the mid-20 mph range, there are likely newly formed deep wind slabs on lee aspects. These fresh slabs may have developed over a crust formed on 4/18 on southern aspects and possibly weaker snow on true north aspects. Monday night may bring an additional 3-6 inches of snow with higher accumulations near the Cascade crest and winds shifting from easterly to westerly. So expect wind slabs of varying ages on opposing aspects and in potentially unusual locations. Visual clues such as textured surfaces, cornices, and pillow-like drifts of snow can help you identify and avoid fresh wind slabs, while you may need to use a probe or pole to feel for stiffer layers in the upper snowpack to identify older, more stubborn wind slabs. Avoid steep terrain near ridges in alpine terrain, and consider sticking to wind-sheltered or lower angle slopes at lower elevations. 

    With minimal direct observations and uncertainty about the distribution and sensitivity of these overlapping wind slabs, it is important to enter new alpine terrain slowly and make observations before committing to steep terrain in wind-affected areas. If you see signs of instability such as shooting cracks or feel the snowpack collapse beneath you, move to lower angle or wind-sheltered terrain.

    (4/11/2022) Wind slabs were found in some unusual spots. Fresh slabs were observed on slopes often stripped by the wind. Photo: Dallas Glass

Avalanche Discussion

While we anticipate a mostly cloudy day with showers and lowering freezing levels for Tuesday, there is a chance of some sun breaks. New snow can quickly turn wet and heavy in the intense spring sun, making wet loose avalanches possible. So if you find yourself on slopes in direct sun with snow surfaces becoming moist or rollerballs forming, it will be best to move to lower angle or shady terrain. Even a small wet loose avalanche could be consequential if it knocks you off your feet and carries you into trees, rocks, over cliffs, or buries you in confined terrain. Spring weather in the Cascades is notoriously tricky and can change rapidly. If you are out adventuring during the long days, keep your senses tuned into the snow and look for signs of deteriorating snow stability.Before Monday's storm, the snow over the 4/8 crust was up to about 4 feet at upper elevations, and I expect Monday brought another 6-10 inches of snow at elevations above 4000ft. On Sunday, an observer from the Teanaway area found 1-2 feet of snow over the 4/8 crust near Jolly Mountain. We lack direct information from many locations in the East Central, but most areas likely have multiple feet of new snow over this thick crust as well. Please help us finish the season strong and submit an observation to the platform if you make it out. 

Régions couvertes