Bulletin d’avalanche

Sea To Sky

Dec 4 – 5, 2011Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Gusty winds have redistributed surface snow creating pockets of wind slab on a variety of aspects. Above freezing temps will likely make wind slabs a bit easier to trigger on steep sun exposed slopes.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–5
    This weakness is getting harder to trigger, but has not gone away. The right trigger (big air onto steep unsupported slope, sled track trenching deep) could have disastrous consequences. Avoid thin-rocky areas where triggering is more likely.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

High pressure is currently dominating the weather throughout the province. Freezing levels rocket to 3000m as an inversion creeps into the region & winds at ridge top are forecasted to be light out of the NW. No precipitation is expected Monday.A weak disturbance moves into the area Tuesday night continuing through Wednesday bringing a small amount of precipitation & lowering freezing levels. The dreaded ridge of high pressure builds back into the area on Thursday.

Avalanche Summary

Avalanche activity has tapered off throughout the week. Although the likelihood of triggering avalanches is lower, the potential consequences are still very high.Likelihood of avalanches may increase on steeper, sun exposed slopes with forecast rising temperatures.

Snowpack Summary

Moderate to strong winds from different directions have hit the region over the past 2 days. As a result pockets of windslab may still be lingering on various aspects at treeline and in the alpine. Deeper in the snowpack we are dealing with a complex and somewhat unusual snowpack for the South Coast. Around Whistler there are persistent weak layers deep in the snowpack including a layer of depth hoar right near the base of the snowpack and at least two distinct crust/facet combinations between 50-100cm above the ground. Recent storms have dumped up to 200cm of snow on top of the weak underlying snowpack. Time has allowed the overlying snow to gain strength making it less likely to trigger the deeper weaknesses, but if you do hit the sweet spot the resulting avalanche could have very serious consequences. The greatest concern is with complex, rocky slopes above 1900m that have not recently avalanched.

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