Bulletin d’avalanche

Northwest Inland

Dec 3 – 4, 2017Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Warmer temperatures expected in the alpine by Tuesday with a strong temperature inversion by Wednesday. Avalanche hazard will likely increase during this time of change.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    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. Signs of wind affected snow include whumpfing and cracking.

  • Deep Persistent Slabs

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

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Monday: Mix of sun and cloud with new snow 5-10 cm. Alpine temperatures near -8 and Freezing levels rising to 700 m. Ridgetop winds strong from the west. Tuesday: Mix of sun and cloud. Alpine temperatures near -2 and freezing levels 1000 m. Ridgetop winds moderate from the west.Wednesday: Sunny with valley cloud and alpine temperatures reaching a high of plus 7. Freezing levels 400 m with a very strong alpine temperature inversion. Ridgetop winds light from the southwest.Expect strong inversions in the alpine up to 3000 m. For detailed information visit the Mountain Weather Forecast.

Avalanche Summary

No recent avalanche activity has been reported. Stiff wind slabs may exist at treeline and in the alpine on leeward slopes and cross-loaded features. If triggered, these could step down and trigger deeper weak layers, initiating large avalanches. The last significant avalanche observation was submitted on November 28th from Skilokis Cr. A size 2.5 persistent slab was triggered from 150 m distance away. This problem will likely linger. Check out the Mountain Information Network for more details. Give info, get info.

Snowpack Summary

Alpine snow surfaces are likely wind affected with 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. Recent snowpack tests have shown sudden planar results at this crust interface. These crusts are widespread and extend well into the alpine. Below these crusts exists a well settled mid pack overlying the late October crust near the base of the snowpack. This late October "crust/facet combo" is widespread and has been reactive to rider triggers.

Régions couvertes