Avalanche forecast

South Rockies

Dec 11 – 12, 2013Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Winds from the SW have developed wind slabs at higher elevations on lee slopes and behind terrain features. Avoid cross-loaded slopes.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Sugary facets near the base of the snowpack represent the most worrisome layer at this time. A surface hoar layer 30-40 cm down may be easily rider triggered with forecast new snow and warmer temperatures.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The South Rockies will begin to see mostly light amounts of new snow, gradual warming and strong ridgetop winds as the weakening cold front passes through on Thursday. Thursday: Cloudy with some flurries. Alpine temperatures near -8. Ridgetop winds moderate from the SW.Friday: Precipitation will taper off as we see a break in the system. Cloudy skies, a trace of new snow. Alpine temperatures -7. Ridgetop winds moderate from the SW.Saturday: Cloudy with snow amounts 5-10 cm. Alpine temperatures -4. Ridgetop winds moderate from the SW gusting to 100 km/hr.

Avalanche Summary

No new avalanche observations have been reported, however I suspect that wind slabs may be easily rider triggered. Use extra caution on cross-loaded slopes, and in the immediate lee of ridgelines. Small loose dry avalanches are likely from steeper slopes, and do not support a significant problem unless you were pushed into a terrain trap like a cliff, or a gully.

Snowpack Summary

Incremental snowfall amounts have begun to bury surface hoar and a faceted upper snowpack. Snowpack depths at treeline seem to vary from 50 - 110 cm and widespread wind effect is noticeable in the alpine and at treeline.Down 30-40 cm sits a surface hoar/ facet/ crust interface. Snowpack testing showed easy results and some whumphing (failure of a weak layer below your feet). If you're seeing or feeling this, consider it a direct indicator of a buried weakness below.Near the base of the snowpack, weak sugary facets and depth hoar exist. This layer may be stubborn to trigger, especially in deeper snowpack areas. In shallower locations the likelihood may increase especially on a steep, convex slope.In some areas it is below threshold below treeline, and early season hazards like open creeks, and stumps exist.

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