Bulletin d’avalanche

East Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

You can easily trigger slab avalanches on wind drifted slopes near and above treeline.  Use caution on all slopes steeper than 35 degrees, as you may also be able to trigger avalanches at lower elevations. Dangerous conditions have been brought on by a potent winter storm delivering strong to extreme winds with 6-8" of snow near Washington Pass by Monday. 

Problèmes avalancheux

  • Wind Slabs

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

    The safest option is to stick to wind-sheltered slopes below treeline. Stay off of wind-loaded, leeward slopes that are 35 degrees and steeper. Steer around drifts, wind features, and convex rollovers. Look for signs of instability such as shooting cracks, blowing snow, and fresh avalanches. Very strong, westerly winds may build slabs further downslope than usual. You may be able to trigger wind slab avalanches below treeline on slopes that are exposed to wind near divides at the Cascade crest. 

    The strong west winds will add to existing cornices. Give them plenty of room when traveling on ridges and stay out from under them.  Travelers are surprised every season when cornices break further back than they expect. 

    (3/24/2021) Overhung cornices in Cutthroat Creek, 6,400ft, ENE. Photo: Josh Hirshberg

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1

    Breaks in the clouds could trigger wet loose avalanches on steep, sun-exposed slopes in the afternoon. This is more likely further east of Washington Pass. Look for signs of instability such as rollerballs and fan-shaped avalanches as the temperature warms. The size of wet loose slides will increase at higher elevations. Use caution on very steep slopes and near terrain traps where these avalanches could be dangerous.

    (3/24/2021) A number of small natural loose avalanches and overhung cornices in the Cutthroat drainage. ENE, 7,300ft. Photo: Josh Hirshberg

Avalanche Discussion

A strong winter storm is impacting the area. The storm brought heavy snowfall rates late on Sunday with strong to extreme westerly winds. While snowfall should slow by Monday morning, winds may keep transporting snow near and above treeline. As typical, areas closer to the Cascade crest will receive the most snow and will have the most elevated avalanche danger. 

On Saturday, observers near Washington Pass were still reporting cold, dry snow on north aspects above 6500'. On Wednesday, an observer in the Cutthroat drainage reported triggered and natural loose avalanches on a variety of slopes 40 degrees and steeper. They also reported a large glide avalanche in Cutthroat at around 5,400ft that appeared to have occurred since March 21st. Since the beginning of March, the region has undergone a slow warming trend. Observers have reported sporadic cornice fall.  The mid-January weak layer that plagued most of the Cascades for the month of February has not been a major concern near Washington Pass.

Régions couvertes