Bulletin d’avalanche

Northwest Coastal

Jan 6 – 7, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

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

Outflow winds may develop new wind slabs at all elevations. New wind slabs may be sitting on a weak layer of surface hoar or sun crust that can act as an easy sliding layer.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Strong outflow winds continue to build wind slabs. Outflow winds have been strongest in areas near the coast and adjacent to large low level valleys.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    A few surface hoar layers buried in mid December are becoming unlikely to trigger; however, some snowpack tests are still showing sudden results. Use extra caution on steep, unsupported slopes at treeline and below.

Avalanche Summary

Some natural wind slab activity size 2.0 was reported from the north of the region near the coast where the outflow winds were reported to be strong. There have been no reports of avalanches from the ski operations in the south or from MIN reports.

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Outflow winds on Wednesday are expected to continue overnight and on Thursday. Some chance of a weak above freezing level developing on Thusday at about 1500 metres elevation. The valleys should stay below freezing as outflow winds carry cold air out towards the coast. On the coast expect freezing levels to rise up to about 700 metres. Light flurries are possible close to the coast, and broken skies are more likely as you move inland. Southwest winds developing on Saturday in advance of a possible storm starting on Sunday.

Snowpack Summary

Snowpack surfaces are highly variable. Temperature inversions and solar radiation have recently come into play and a melt-freeze crust can be found on steep, solar aspects in the alpine. On most other slopes, 25-40 cm of snow from the Boxing Day storm continues to settle and facet, and new surface hoar has been reported although its distribution is likely variable due to strong outflow winds. In areas where recent winds have been light, shaded slopes will likely provide settled powder. In areas where winds have been stronger, reactive wind slabs may exist, especially in areas where the the slab overlies surface hoar buried by the Boxing Day storm. Professionals in the region are still keeping an eye on a few other surface hoar layers that developed throughout December which are now buried in the top 100cm. Although these layers may be gaining strength, they are worth keeping an eye on, especially on steep unsupported slopes at treeline and below. In colder and shallower snowpack areas watch for weak basal facets.

Régions couvertes