Bulletin d’avalanche

Northwest Inland

Dec 2, 2017Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Points saillants

The late October crust near the base of the snowpack is reactive to rider triggers producing large avalanches. Its possible to trigger this from a significant distance away. Heads up out there as this problem will likely persist.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Recent snow and wind have formed touchy wind slabs. Expect these slabs to be more pronounced at higher elevations and on leeward aspects. Watch for signs of wind affected snow, whumpfing and cracking.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    The late October crust lies near the base of the snowpack with a thin layer of weak, sugary snow above it. This layer has been reactive to rider triggers and remote triggering has occurred producing large avalanches.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Saturday: Mostly cloudy with isolated flurries and alpine temperatures near -15. Ridgetop winds light from the North West and freezing levels at valley bottom.Sunday: Mostly cloudy in the valley with sunshine at higher elevations. Alpine temperatures near -12and freezing levels at valley bottom. Ridgetop winds light from the West.Monday: Cloudy with new snow amounts 5-10 cm. Ridgetop winds moderate from the South West. Alpine temperatures rising to 0 degrees and freezing levels near 1100 m.

Avalanche Summary

No recent avalanche activity has been reported. I suspect stiff wind slabs exist at treeline and in the alpine on leeward slopes and behind terrain features. If triggered, these wind slabs could step down and trigger deeper weak layers within the snowpack initiating large avalanches. If you get out this weekend please submit your observations to the Mountain Information Network.

Snowpack Summary

Alpine snow surfaces are likely wind affected with the average snowpack depths 80 cm -140 cm at treeline elevations, and up to 160 cm in the alpine. Approximately 30-50 cm of recent snow now overlies two crusts that were buried near the end of November. Reports indicate that these crusts extend well into the alpine and seem to be supportive to rider traffic. Below these crusts is a well settled mid pack that sits on the late October crust close to the base of the snowpack at all elevations. This late October "crust/facet combo" is widespread and has been very reactive to rider triggers producing large avalanches.

Régions couvertes