Bulletin d’avalanche

East Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Intense snowfall and extreme winds will create very dangerous avalanche conditions. You can trigger avalanches in wind-drifted snow in unusual locations, and a widespread natural avalanche cycle is likely at upper elevations. Avoid traveling in and near steep terrain while this storm plays out. 

 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1.5–2.5

    The snow totals alone with this storm will be impressive, and intense precipitation rates will lead to a widespread avalanche cycle. However, rapid wind loading will likely create the most dangerous avalanche conditions. You can expect an average of 40-50mph winds, with occasional stronger gusts. These strong winds and the intense snowfall will quickly build thick wind slabs on all aspects and elevations. You may find wind slabs at lower elevations and in unusual places typically sheltered from the wind. Some atypical locations you could trigger a wind slab would be farther downslope below ridges, moderately spaced trees, or small clearings in forested areas. Cornices will also build quickly and be sensitive to triggering.It will be best to avoid avalanche terrain on Monday while this storm runs its course. A natural avalanche cycle is likely near and above treeline. Avoid being underneath steep terrain at upper elevations. If traveling at lower elevations below treeline, avoid slopes over 35 degrees and stick to wind-sheltered areas. Even in wind-sheltered terrain, triggering an avalanche on a steep slope may be likely, so make sure to give yourself a wide margin of safety in your terrain selection. Look for the red-flag signs of instability, such as recent avalanches, collapsing, or shooting cracks. 

    (1/7/2022)

    Intense wind drifting of the snow is certain on Monday.

    Photo: Matt Primomo

Avalanche Discussion

The weather is about to drastically change from what we have experienced for the last couple of weeks. The mountains will get hammered on Sunday night and Monday with heavy precipitation and very strong to extreme winds. With a warm start to the storm, it may take a bit for lower elevations to accumulate snow, but upper elevations will likely see upwards of a foot of new snow by the early morning hours of Monday. As the trailing cold front passes, temperatures will drop quickly, and the snow will continue to stack up. Areas in the zone close to the crest may see over 2 feet of snow by Monday night, while locations further east, like Mission ridge, will likely pick up around one foot.

Depending on aspect and elevation, new snow will fall on a wide variety of surfaces. At upper elevations, slick, icy crusts may be a good sliding surface, and weak snow on the surface could be a potential weak layer. Some slopes were snow-free on southerly aspects below 5000ft. Use extra caution in these lower elevations where hidden obstacles may be lurking just under the new snow, and creek holes may become drifted over and hidden.

Régions couvertes