Bulletin d’avalanche

South Rockies

Mar 28 – 29, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Sat
Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Wind loaded and cross-loaded slopes can still be found at treeline and alpine elevations. A small wind slab avalanche could step down to the March 16th rain crust. Wind slabs may be triggered under the weight of a skier, rider or cornice fall.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    Large looming cornices exist on most ridgelines. Cornices may become weak under the influence of the sun. They are a hazard in themselves and they could trigger slopes below.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    Warmer afternoon temperatures and sunshine may promote deterioration within the upper snowpack. If surface snow becomes moist or wet, loose wet avalanches are likely. Watch solar aspects.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

The region will be under a fairly dry NW flow. A mix of sun and cloud with possible light precipitation amounts Friday afternoon. Spring-like conditions persist through the weekend with clear, sunny, warm temperatures during the day and slight cooling  overnight. Alpine temperatures are expected to reach around zero degrees and little wind is forecast.Friday: Scattered cloud. Alpine temperatures reaching 0.0 degrees. Freezing levels rising to 2500 m in the afternoon then dropping  1300 m overnight. Ridgetop winds will blow light from the West.Saturday: Few clouds. Alpine temperatures reaching 0.0 degrees. Freezing levels rising to 2600 m in the afternoon then dropping to 1500 m overnight. Ridgetop winds blowing light from the West.Sunday: Mostly sunny. Alpine temperatures -6.0. Freezing levels 1700 m  and then falling to valley bottom overnight.

Avalanche Summary

On Thursday, several loose wet avalanches size 1 initiated from steep Southerly terrain. 

Snowpack Summary

Cornices are large and will likely become weak due to strong solar radiation and warming temperatures. The surface snow has become moist or wet up to 2200 m, especially on solar aspects. Melt-freeze conditions exist. Wind slabs exist in the immediate lee of ridge lines and terrain features. Surface hoar and surface facetting is forming on sheltered, northerly aspects, especially at higher elevations. Approximately 40-70 cm of settling storm snow sits on top of a buried rain crust down 50 cm and exists up to around 2100 m. The bond of this snow to the crust has shown variability though the region. It is important to dig down and test weak layers before dropping into your line. A large trigger such as a cornice fall or a skier/sledder hitting the sweet spot, could potentially trigger a large avalanche on this layer.

Régions couvertes