Avalanche forecast

South Rockies

Jan 2, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The base of the snowpack is weak. It will remain likely for a while that humans can trigger deep persistent slabs.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Wind slabs may linger in wind-loaded terrain features at higher elevations.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3
    Around 60 to 90 cm of snow sits on a weak layer of sugary faceted snow. The snow beneath this is also weak and faceted, all the way to the ground. Avalanches triggered on this layer will likely scour to the ground, resulting in large avalanches.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TUESDAY NIGHT: Partly cloudy, moderate west winds, freezing level below valley bottom.WEDNESDAY: Mostly cloudy, moderate to strong west winds, alpine temperature -8 C, freezing level below valley bottom.THURSDAY: Cloudy with light snowfall, strong southwest winds, alpine temperature -3 C, freezing level rising to 1500 m.FRIDAY: Cloudy with light snowfall, accumulation 5 to 10 cm, moderate to strong southwest winds, alpine temperature -5 C, freezing level 1500 m.

Avalanche Summary

No new avalanches were observed on Monday. Several loose dry avalanches and a few small (size 1) storm slab avalanches were triggered by skiers in this region on Sunday.

Snowpack Summary

Large variability in snow depths still exists in the region, ranging from practically no snow to almost 200 cm. For areas with sufficient snow, the upper snowpack consists of hard wind slabs on all aspects due to variable wind directions, a scoured and shallow snowpack on exposed southerly ridges, and generally soft snow in sheltered areas.Around 60 to 90 cm of snowfall in December has formed a slab that sits on a persistent weak layer of weak and sugary faceted snow that formed during dry and cold weather in early December. This layer is most likely to be triggered on steep features where snowpack depths are variable.The lower snowpack has a weak structure composed primarily of sugary faceted snow around a crust near the ground. Should a shallower avalanche be triggered, it is likely that it would step down and scour to the ground.

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