Bulletin d’avalanche

Northwest Inland

Feb 22 – 23, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

In the North of the region avalanche danger in the Alpine is likely to be Considerable due to the presence of a recently reactive layer of facets near the ground.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Reactive slabs maybe found on freshly wind loaded alpine features. The sun may have enough punch on Tuesday to trigger natural avalanche on slopes that see direct sunlight.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    A layer of buried surface hoar remains a concern. Large avalanches can be triggered from thin spots or by heavy loads such as cornice releases. Smaller avalanches in motion have the potential to step down to these layers.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    3–5
    Large avalanches have recently released on facets at or near the ground north of Bell2.  This is probably a problem confined to the north of the region where the snowpack is thinner.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

TUEDSAY: mainly sunny, moderate southerly winds, freezing level 800m falling to valley floor again overnight. WEDNESDAY: flurries overnight partly cloudy, moderate southwesterly winds, freezing level 1200m. THURSDAY: flurries, moderate to strong southwesterly winds, freezing levels between 1200 and 1500m.

Avalanche Summary

Isolated wind slab avalanches were reported over the weekend. In the north of the region, a small natural avalanche that stepped down to the early January surface hoar on Sunday is a good reminder that this layer needs to remain a concern.  Deeply buried persistent weak layers in the alpine also woke up in the north of the region over the weekend when several large avalanches released on basal facets.  This weak layer was reported to be reactive to skier triggering from thin spots, as well as heavy triggers such as a smaller avalanches or cornice failures.

Snowpack Summary

Alpine areas are reported to be widely wind effected with wind pressed surfaces found in exposed areas and a mixture of hard and soft slabs present in lee features. A thin crust may cap moist snow at or just below the surface at lower elevations and on slopes that see direct sun. The upper snow pack is reported to be bonding well to a crust buried on February 12th, now 40 to 80cm down, that extends up to around 2000m. The early January surface hoar can be typically be found between 60 and 140cm down.  Although it is getting harder to trigger it remains a concern.  Shallow snowpack areas also have a weak base layer of facetted snow just above the ground.

Régions couvertes