Bulletin d’avalanche

North Columbia

Feb 7, 2019Avalanche Canada
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Archivé · expiré 8 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

There is a potential for triggering large avalanches at lower elevations due to the presence of a buried weak layer that exists mainly at treeline and below.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    30-80 cm of recent snow has been redistributed by north and east winds over the past couple of days.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1.5–3
    50-100 cm of snow is now sitting on a persistent weak layer of surface hoar and crust that was buried in mid January. This region has been the "hot spot" of activity on this layer, with more reactivity reported here than in neighboring regions.

Confidence

High - The weather pattern is stable

Weather Forecast

THURSDAY - Mainly cloudy with light flurries, accumulation 5 cm / light southwest winds / alpine high temperature near -15FRIDAY - A mix of sun and cloud / moderate northeast wind / alpine high temperature near -17SATURDAY - A mix of sun and cloud / moderate northeast wind / alpine high temperature near -20

Avalanche Summary

A persistent weak layer that was buried in mid January continues to be reactive to human triggers. This layer is sensitive enough for avalanches to be triggered remotely (from a distance). Skier and snowmobile triggered avalanches up to size 2.5 were reported on both Sunday, Monday and Tuesday. This layer is the most reactive at treeline and below. This MIN report from Monday does a great job of illustrating the sensitivity of this weak layer.Human triggered avalanches failing on the mid January persistent weak layer have been reported almost daily for the past two weeks in the North Columbia region.

Snowpack Summary

30-80 cm of recent new snow sits on surface hoar (feathery crystals), facets (sugary snow), wind slabs and a crust on sun-exposed slopes. In many areas, recent winds have redistributed the new snow, forming wind slabs on all aspects due to shifting wind directions.The most notable feature in the snowpack at this time is a persistent weak layer that was buried in mid January, which is now buried 50-100 cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer is the most prominent at treeline and below, and continues to be produce avalanches.

Régions couvertes