Avalanche forecast

South Rockies

Feb 10, 2017Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

A Special Public Avalanche Warning applies to this region.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3
    Additional new snow, warmer temperatures and wind have created touchy new moist storm and wind slabs

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4
    A weak layer at the bottom of the snowpack is creating the potential for full depth avalanche releases. Storm slab avalanches have the potential to step down to this layer. This is most likely in the thin snowpack areas of the region.

Confidence

High -

Weather Forecast

FRIDAY: Scattered flurries, accumulation 5cm / Moderate to strong west wind / Alpine temperature -8SATURDAY: Mix of sun and cloud / Moderate west wind / Alpine temperature -11SUNDAY: Cloudy with isolated flurries / Moderate west wind / Alpine temperature -7More details can be found on the Mountain Weather Forecast.

Avalanche Summary

On Thursday there was a report of a size 2.5 natural avalanche 50-120cm deep on a NW aspect in Waterton Park. Expect the recent dense storm slab to be reactive to human triggering in the coming days as the all the new snow from the past 10 days starts to settle. Storm slab avalanches have the potential to step down to the basal weakness which would drastically increase the size and destructive potential of a resulting avalanche.

Snowpack Summary

Thursday saw 15-30cm of moist new snow fall on top of the 90cm of low density storm snow that accumulated last weekend. Strong shifting winds have redistributed the previous storm's snow in exposed terrain forming touchy wind slabs. These wind slabs are now obscured by the latest blanket of snow. All this overlies a highly variable old surface which may include wind affected surfaces, facets, and/or a rain crust below around 1500 m. Recent reports suggest a poor bond between the storms' snow and the old surface. In deeper areas, the snowpack appears to be well settled with isolated concerns about the mid-December facet layer which was buried 50-100 cm deep prior to the weekend storm. In shallow snowpack areas and at lower elevations, the snowpack is weak, faceted, and has no structure. Prior to the storm, it was possible to step onto the snow surface in these areas and sink right to the ground.

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