Avalanche forecast

North Columbia

Feb 9, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Sun
Mon
Alpine
2 · Moderate
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Large human triggered avalanches continue to be triggered at and below treeline due to the presence of buried surface hoar. Click here to see our Forecasters' Blog for a more detailed description of current conditions.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    30-80 cm of recent snow has been redistributed by north and east winds over the past couple of days.  Winds out of the east/southeast Saturday may form wind slabs in unusual locations.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1.5–3
    50-100 cm of snow is now sitting on a persistent weak layer of surface hoar and crust that was buried in mid January. This layer continues to produce spooky large human triggered avalanches in the trees, in terrain that is seemingly benign.

Confidence

Moderate -

Weather Forecast

Cold, dry, arctic air continues to dominate the weather pattern for the foreseeable future.FRIDAY NIGHT: Freezing level at valley bottom, around -25 C in the alpine, potentially strong valley bottom wind event, light to moderate southeast wind in the alpine, trace of snow possible.SATURDAY: Scattered cloud cover at dawn with clouds steadily clearing through the day, freezing level at valley bottom, around -25 C in the alpine, light winds at most elevations, light to moderate east/southeast wind at ridgetop, no significant snowfall expected.SUNDAY: Clear skies, freezing level at valley bottom, around -20 C in the alpine, potentially strong valley bottom wind event, light southeast wind in the alpine, no significant snowfall expectedMONDAY: Scattered cloud cover, freezing level at valley bottom, around -20 C in the alpine, light variable wind at all elevations, no significant snowfall expected.

Avalanche Summary

A persistent weak layer that was buried in mid January continues to be reactive to human triggers. This layer is sensitive enough for avalanches to be triggered remotely (from a distance). Skier and snowmobile triggered avalanches up to size 2.5 were reported on Sunday, Monday, Tuesday and Thursday.  This layer is the most reactive at treeline and below. This MIN report from Monday does a great job of illustrating the sensitivity of this weak layer.Human triggered avalanches failing on the mid January persistent weak layer have been reported almost daily for the past two weeks in the North Columbia region.

Snowpack Summary

30-80 cm of recent new snow sits on surface hoar (feathery crystals), facets (sugary snow), wind slabs and a crust on sun-exposed slopes. In many areas, recent winds have redistributed the new snow, forming wind slabs on all aspects due to shifting wind directions.The most notable feature in the snowpack at this time is a persistent weak layer that was buried in mid January, which is now buried 50-100 cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer is the most prominent at treeline and below, and continues to be produce avalanches.

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