Avalanche forecast

South Rockies

Jan 18 – 19, 2012Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–5
    Wind slabs have formed mainly on east aspects. Large wind slabs released during the storm. Further avalanches could be triggered by the weight of a person, sled or cornice fall.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–7
    A buried surface hoar layer in the top metre of the snowpack continues to be a concern. Although it has become stubborn to trigger, the consequences are high. It's most likely to be triggered from shallow rocky areas on a slope, or by a large load.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    A lot of very dry, loose snow has built up. This has shown the ability to run fast and far, picking up considerable mass as it travels.

Confidence

-1 - -1

Weather Forecast

Thursday: A mix of sun and cloud, with a few afternoon flurries. High near -17.Friday: Cloudy with morning sunny breaks, 70% chance of afternoon flurries. High near -12. Snow and trending milder Friday night, light to moderate accumulation. Saturday: Periods of snow, moderate accumulation. High near -5.

Avalanche Summary

A widespread natural avalanche cycle occurred in the Elk Valley on Tuesday/ Tuesday night, with numerous slabs up to size 3 releasing in the alpine on mainly east-facing slopes. Initial reports suggest that these released up to 2m deep on wind-loaded slopes. South of the Crowsnest, a few size 1-2 slabs were reported.

Snowpack Summary

Storm snow totals average around 40cm, with local variability. Cold temperatures have limited storm slab development, however numerous slabs did release during peak loading during the storm. In many areas, fast-moving sluffs remain a key concern. Besides new storm/wind-related concerns, the main layer we're watching in the region is a surface hoar layer buried in early December. It's down about 1m in the Flathead and recently exhibited hard, sudden planar/full propagation results, meaning that it was stubborn to trigger but could create a large avalanche. Facets sandwiched between two firm layers in the top metre of the snowpack are being monitored in the south-east.

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