Bulletin d’avalanche

Purcells

Jan 19 – 20, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–5
    Wind slabs were formed behind terrain breaks such as ridges and ribs. It may be possible for a wind slab to step down to a deeper instability.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–5
    Triggering persistent slabs is becoming less likely, but a cautious approach is still advised. Take extra care on steep south-facing alpine slopes and in sheltered terrain below treeline.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday night and Sunday:  Ridge of high pressure continues to dominate for the whole period. No precipitation, mild temperatures, broken clouds and valley clouds and moderate Westerly winds becoming light on Sunday.Monday: Similar conditions with warmer temperatures and freezing level rising to 1400 m. Tuesday: Dry conditions persist, light SW winds and freezing level around 1300 m.

Avalanche Summary

A slab avalanche size 2 was reported from the Jumbo area. It would have been triggered by a cornice fall on a steep alpine slope.

Snowpack Summary

Recent strong to extreme NW to SW winds have stripped windward aspects and left wind slabs on many lee slopes, even below treeline. Around 40-60 cm settled storm snow sits above surface hoar (found especially at and below treeline in sheltered areas), a sun crust (on steep S to SW -facing slopes) and facets. The distribution of these weaknesses is patchy, but where they exist, it may still be possible to trigger a large avalanche with the weight of a person or snowmobile. Test results on these interfaces vary from no result to moderate, sudden results. They appear to be more reactive in the middle part of the region rather than in the Northern part of the region. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Régions couvertes