Avalanche forecast

South Columbia

Feb 24 – 25, 2013Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–6
    Storm loading has added additional stress to a persistent weak layer of surface hoar or a sun crust which now lie up to 100cm below the surface. Triggering this weakness may result in surprisingly large avalanches.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    A storm forecast for late Sunday will add to recent heavy accumulations. Watch for increased slab reactivity in wind-affected terrain. In sheltered areas, the new snow may also react as a loose dry avalanche.

Confidence

Fair - Intensity of incoming weather is uncertain on Sunday

Weather Forecast

Sunday night and Monday: Heavy snowfall becoming light on Monday / Strong west winds becoming light northwesterly on Monday / Freezing level at 800mTuesday: Mix of sun and cloud / Light southwest winds / Freezing level at 1000mWednesday: Light snowfall / Light southwest winds / Freezing level at 900m

Avalanche Summary

Revelstoke RCMP confirm one skier has been killed in an avalanche which occurred in the Greely Lake area, well outside of the controlled area boundaries of the Revelstoke Mountain Resort on Friday afternoon. For more details on the incident, please follow this link: Incident ReportElsewhere in the region many avalanches to size 2.5 were observed on a variety of aspects and elevations. They occurred in response to intense wind and heavy snowfall on Friday. Avalanches in this cycle ran as loose dry and storm slab avalanches, while many failed at the persistent February 12th interface.Storm snow instabilities are expected to ramp up again on Sunday night with forecast weather.

Snowpack Summary

Up to 60cm of recent snow and wind created potent new storm slabs which seem to be most reactive in wind-exposed terrain. These heavy accumulations add to the 30 to 60cm of snow which overlie the weak surface hoar layer which was buried on February 12th. The additional weight of the new snow and wind affect is expected to add reactivity to this persistent weakness which remains a primary concern for professionals in the region. This interface has also shown reactivity on southerly aspects where a sun crust formed during the period from February 8th-11th. The mid to lower snowpack are generally strong and well settled. I would expect significant cornice growth with the current weather pattern, and expect them to be weak and potentially destructive.

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