Bulletin d’avalanche

Northwest Coastal

Feb 20 – 21, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

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

Slabs may remain triggerable at upper elevations where dry snow has been wind loaded into leeward terrain features. Watch for signs of instability like cracking and recent avalanches.

Problèmes avalancheux

  • Wind Slabs

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

    Slabs may remain reactive to human triggers in wind-loaded terrain features like ridge crests and convexities.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Large, looming cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures are dangerous on their own, but they also have potential to trigger large persistent slab avalanches that would otherwise be difficult to trigger.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

Saturday night: Mostly cloudy with flurries up to 5 cm, moderate northwest wind, freezing level dropping to 500 m.

Sunday: A mix of sun and clouds with isolated flurries, light to moderate northwest wind, high of -2, freezing level 500 m.

Monday: Sunny, strong northeast wind, alpine high of -15, freezing level valley bottom.

Tuesday: Increasing cloud, light northwest wind, alpine high of -10.

Avalanche Summary

On Thursday and Friday, natural wet loose avalanches were reported up to size 2. Skier and explosive triggered storm and wind slabs were also reported size 2.

 

Snowpack Summary

30-50 cm of recent snow sits over a widespread 10-30 cm thick rain crust at all elevations. At upper elevations, the recent snow has been wind affected. At mid elevations, it may contain a thin rain crust. Below 1300 m, moist surfaces will refreeze as temperatures drop this weekend.

The thick rain crust beneath the recent snow effectively caps the underlying snowpack, making human triggering of avalanches on deeper weak layers very unlikely. However, cornice failures may still have potential to trigger these deeper weak layers, resulting in very large avalanches.

Terrain and Travel

  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Be careful as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Start with conservative lines and watch for clues of instability.
  • Extra caution is needed around cornices under the current conditions.

Régions couvertes