Avalanche forecast

South Columbia

Mar 9 – 10, 2013Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Large and weak cornices may fail, especially during periods of warming or solar radiation. A cornice fall could trigger a large slab avalanche on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–7
    A weak layer of buried surface hoar down about 100-150 cm may be triggered by large loads like re-grouping, cornice fall, or smaller avalanches in motion. Strong solar radiation may initiate this layer where it sits on a crust.

Confidence

Poor - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Sunday: Increasing cloud with a chance of flurries late in the day. The freezing level climbs to 1500 m during the day. Winds are moderate from the west-southwest. Monday: Sunny breaks and a chance of flurries. Temperatures are a degree or two cooler with the freezing level around 1000 m. Winds ease to light from the northwest. Tuesday: Moderate snow. The freezing level could rise to around 1600 m and winds increase to moderate or strong from the southwest.

Avalanche Summary

Loose snow sluffing continues in steep terrain on all aspects. On Thursday there was a report from the Central Selkirks of a chunk of snow that fell out of some cliffy terrain at treeline which triggered and propagated three progressively deeper slabs resulting in a size 2.5 avalanche sliding on the February 12th weak layer down about 100 cm.

Snowpack Summary

A fairly widespread layer of surface hoar, mixed with a dusting of new snow in some areas, is sitting above various sun crusts and old storm slabs. The storm slab continues to settle, and is becoming more stubborn to trigger. The weak layer of surface hoar that was buried on February 12th is now down about 100-150 cm and continues to be triggered by light additional loads on Southerly aspects where it is sitting on an old sun crust. Larger loads like cornice fall or explosives have been able to trigger this layer on various aspects in the alpine and at treeline. If the we get a period of strong solar radiation, then we may see another cycle of natural activity on Southerly aspects resulting in large destructive avalanches.

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