Bulletin d’avalanche

Northwest Coastal

Feb 19, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré

Points saillants

Strong outflow winds have created very touchy wind slabs. Be cautious in terrain features where snow has accumulated, as the slabs will likely be easy to trigger.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Strong to extreme winds have produced stiff and touchy wind slabs in lee and cross-loaded features. These slabs will be reactive to both natural and human triggers.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY: Partly cloudy with increasing cloudiness, moderate northwesterly winds, alpine temperature -9 C, freezing level below valley bottom.TUESDAY: Mostly sunny, light to moderate northerly winds, alpine temperature near -8 C, freezing level below valley bottom.WEDNESDAY: Mostly sunny, moderate to strong northerly winds, alpine temperature near -5 C, freezing level below valley bottom.

Avalanche Summary

Many small to large (size 1 to 2) wind slabs were reported on Saturday in steep alpine and cross loaded terrain. They were reported to have released naturally and by skiers due to rapid wind loading from strong northeasterly winds. A small cornice failure was also noted.

Snowpack Summary

Strong northeast outflow winds have redistributed the 40-60 cm of snow that fell since Tuesday. The winds have produced touchy wind slabs in lee and cross-loaded features at all elevations (as observed in this post and this one). This snow sits on a wide variety of surfaces, including wind-scoured and old wind slabs at higher elevations, a sun crust on steep solar aspects, and facets and surface hoar in sheltered locations at treeline and below treeline elevations. The surface hoar and facets are found around 60 to 110 cm below the surface on all aspects up to elevations of 1400 m.A deeply buried crust/surface hoar layer from mid-January exists in sheltered areas at treeline and below treeline elevations. Thin spot triggering is the primary concern for this layer.

Régions couvertes