Bulletin d’avalanche

Northwest Inland

Dec 5, 2017Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

Lingering wind slab and persistent slab problems will keep avalanche danger in a holding pattern for one more day. Warm temperatures are set to undermine stability in the midweek.

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. This layer has recently produced very large avalanches with both rider triggers as well as remote triggers.

Confidence

Moderate -

Weather Forecast

Tuesday: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate west winds. Weak alpine temperature inversion bringing alpine temperatures to around -2.Wednesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light southwest winds. Freezing level rising to over 3000 metres with alpine temperatures around +5. Cooler temperatures at valley bottom due to temperature inversion.Thursday: Mainly sunny with some valley cloud due to lingering temperature inversion. Light to moderate southwest winds. Freezing level to over 3000 metres with alpine temperatures around +5. Cooler temperatures at valley bottom.

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 to trigger deeper weak layers and initiate large avalanches. The last significant avalanche observation was submitted on November 28th from Skilokis Creek. Here, a size 2.5 persistent slab was triggered from 150 m away. This problem will likely linger. Check out the Mountain Information Network for more details. Give info, get info.

Snowpack Summary

Average snowpack depths now total 80-140 cm at treeline elevations and up to 160 cm in the alpine. Alpine snow surfaces are likely wind affected. Below the surface, approximately 30-50 cm of recent snow now overlies two crusts that were buried near the end of November. These crusts are widespread and extend well into the alpine. Recent snowpack tests have shown sudden results at these crust interfaces. Below these crusts, we have a well settled midpack 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 and remote triggers.

Régions couvertes