Bulletin d’avalanche

South Coast Inland

Feb 6 – 7, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

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

Avoid avalanche terrain at treeline where triggering a persistent slab avalanche is most likely. High freezing levels and solar radiation could increase the likelihood of triggering.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    rider triggerable wind slabs will likely exist on east and north aspects at and above treeline.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3

    20 to 50 cm of snow sits over a facet-crust weak layer combination that is possible to human trigger. This problem is particularly concerning in the Duffy Lake area. Recent observations demonstrate the potential for this problem to be triggered remotely and propagate far and wide.

Confidence

Moderate - Uncertainty is due to difficult to forecast freezing levels.

Weather Forecast

Saturday night: no new snow expected. Light to moderate west winds with a low of -6 at 1500m.

Sunday: mix of sun and cloud with no new snow expected. Light to moderate west winds. Freezing level rising to 1500 m in the north and up to 2500 m in the south.

Monday: light precipitation throughout the day bringing up to 5cm of snow with moderate west winds. freezing level around 1400m.

Tuesday: trace amounts of new snow with moderate to strong west winds and a high of -3 at 1500m.

Avalanche Summary

On Saturday a size 3 skier triggered avalanche was reported in the Duffy Lake area. Details are limited but we suspect it ran on the persistent weak layer from late January. This avalanche was triggered in a upper treeline feature and showed significant propagation. 

In the neighbouring Sea to Sky region, we received a report of a large (size 2.5) human-triggered avalanche near Rainbow Mountain that caught and carried a group of five skiers. The avalanche released on north aspect at 1900 m. It broke 40 cm deep on the late January facet-crust layer. The avalanche propagated across adjacent roll-over features and triggered a sympathetic slide on a small feature 200 m away.

Snowpack Summary

10 to 20cm of recent snow accompanied by strong southwest winds on Friday formed new wind slabs on north and east aspects in treeline and above.

Moist snow will likely be observed on south aspects and all aspects treeline and below. 

20 to 50 cm sits above a variety of surfaces including surface hoar, facets and a crust. This layer is most prominent at treeline and above. Especially in the Duffy area.

Terrain and Travel

  • Be aware of the potential for large avalanches due to the presence of buried weak layers.
  • Remote triggering is a concern, avoid terrain where triggering slopes from below is possible
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.

Régions couvertes