Bulletin d’avalanche

South Columbia

Apr 6 – 7, 2015Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Wed
Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Warmth is the primary driver of avalanche hazard and the weather forecast calls for a steadily increasing freezing level over the next few days. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Steadily increasing temperatures for the next few days will likely make cornices more prone to failure. You do not want to be on top of or underneath these large and dangerously heavy pieces of snow when they collapse.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–7
    Human triggered persistent slab avalanches remain a concern. It's tough to say which features harbor a trigger-able weakness and which don't with any amount of certainty.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Anytime previously dry/cool snow experiences the intense kiss of the spring sun, loose wet avalanches are likely. Most south and west facing slopes are probably done, but keep this problem in mind as you piece together travel plans.

Confidence

Fair

Weather Forecast

TUESDAY: Freezing level starting at valley bottom, rising to 1800m. Light variable winds at all elevations. No significant precipitation expected. Clear skies in the morning, cloud cover increasing in the afternoon.WEDNESDAY: Freezing level starting at 900m, rising to 2000m. Light N/NE winds at all elevations. No significant precipitation expected. Mostly clear skies.THURSDAY: Freezing level starting at 1500m, rising to 2200m. Light SW winds at all elevations. No significant precipitation expected. Clear skies.

Avalanche Summary

Reported avalanche activity on Sunday was limited to power sluffing in steep high elevation terrain. On Saturday storm slabs ran to size 1.5 on NE through NW facing features between 1900 and 2700m. Loose dry avalanches to size 1.5 were reported from all aspects between 2000 and 2500m. A few size wet slabs were reported from southerly facing features between 2100 and 2500m. There were a couple noteworthy avalanches from last week. On Thursday a rider was partially buried in a size 2.5 wind slab on a north aspect at 2600m. On Wednesday, a naturally-triggered size 2.5 wind slab was observed on a NE aspect at 2500m. On that same day an ice fall triggered a size 3 deep persistent slab which failed at ground.

Snowpack Summary

Up to 20cm of dry snow may be hiding previously formed wind slabs on upper elevation slopes. These overlie a crust which varies in thickness with elevation. Sun may destabilize new snow and cornices. Below about 2000 m, loose moist snow makes up much of the snowpack underneath a surface crust. Persistent weak layers in the upper snowpack remain a lingering concern. The mid-March crust/facet layer is down around 60 cm. Down around 80 cm is the mid-February crust/facet/surface hoar layer. Both of these layers are slowly improving in strength, although it may still be possible to trigger one of these, causing a very large avalanche.

Régions couvertes