Bulletin d’avalanche

Vancouver Island

Dec 7 – 8, 2021VIAC
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Archivé · expiré 5 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible

Points saillants

Rapid warming will likely further destabilize storm slabs over a slippery crust. As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1.5–2.5

    Rapid settlement due to an overnight spike in temperature will likely further destabilize storm slabs, precariously perched on a slick crust. Over the day, however, the warm temperatures may even facilitate bonding at the snow/crust interface. You can dig down to investigate.

Confidence

Low - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

Monday night: A trace of new snow. Moderate northwest wind. Freezing level rising to 2000 m.

Tuesday: Flurries 5-10 cm. Moderate southwest wind building to strong in the afternoon. Treeline high temperature around +1. Freezing level trending down 2000-1500 m.

Wednesday: Overnight snow 15-20 cm. Strong northwest wind. Treeline high temperatures around -5. Freezing level 700 m.

Thursday: A mix of sun and cloud. Light northwest wind. Treeline high temperatures around -5. Freezing level 800 m.

Avalanche Summary

No recent reports.

Snowpack Summary

A spike in freezing levels overnight will promote rapid settlement in 20-40 cm of recent snow, precariously perched on a slippery crust. In the short term, rapid settlement is a destabilizing process but over they day, the warm temperatures may help the snow bond to the crust.

Underneath this snow, the 5-10 cm thick crust is reportedly supportive to skis but not boots or sleds. Faceting has been observed on its underside.

Recent indications of the region's surviving snowpack suggest alpine depths around 150 cm, depth tapering dramatically with elevation to about 30-60 cm at treeline. Below treeline is largely bare.

Terrain and Travel

  • Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
  • Use small low consequence slopes to test the bond of the new snow.
  • Keep in mind the crust offers an excellent bed surface for avalanches.

Régions couvertes