Bulletin d’avalanche

Sea To Sky

Feb 21, 2018Avalanche Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

The snow is heavily wind-affected. Stick to sheltered trees to find the best and safest riding.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5
    Strong winds from the north have blown recent snow into reactive wind slabs at higher elevations.
  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5
    Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect.

Confidence

High - The weather pattern is stable

Weather Forecast

A fairly benign weather pattern is expected through the forecast period. Wednesday: Cloudy with isolated flurries. Alpine temperatures near -12 and ridgetop winds light to moderate from the West.Thursday: Mostly sunny with some cloud cover. Alpine temperatures near -10 and ridgetop winds light to moderate from the North.Friday: Mainly cloudy with some new snow. Alpine temperatures near -9 and ridgetop winds strong from the southwest.

Avalanche Summary

On Monday, numerous wind slabs and cornice failures were reported. Most wind slabs were reactive to rider triggers, and explosive control up to size 2 on all aspects above 1800 m. The cornice failures were triggered by explosives but not pulling a slab or entraining much mass from the slopes below. With little change in the weather forecast natural avalanche activity will subside, but human triggers remain possible.

Snowpack Summary

In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, especially in the trees the cold weather is preserving 30-40 cm of low density snow. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1900 m, which has supported some wide propagations in recent storm slab avalanches. Deeper in the snowpack, avalanche professionals are still monitoring the mid-January crust. This layer is now 150-200 cm deep, but a heavy trigger (cornice?) or the next major storm (warming and loading) could potentially wake up this layer.

Régions couvertes