Avalanche forecast

South Rockies

Jan 23, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

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

Watch for fresh winds slabs and avoid shallow spots where triggering deeper layers is more likely.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Recent snow fell on weak surface hoar and/or crusts. Wind continues to redistribute loose snow, expect the deepest and more reactive deposits will be in wind-loaded areas.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    Deeply buried weak layers remain a concern. These layers are more easily triggered in areas where the snowpack is shallow, such as near ridges and rocky terrain. Be very suspicious of steep slopes that have yet to avalanche this winter.

Confidence

Moderate - Freezing levels are uncertain on Friday

Weather Forecast

TUESDAY NIGHT: Flurries, trace to 5 cm. Light west-northwest wind. Alpine low -10C, freezing level valley bottom.WEDNESDAY: Cloudy with scattered flurries, trace accumulation. Light to moderate west wind. Alpine high -6C, freezing level 1100 m.THURSDAY: Cloudy with sun and isolated flurries, trace accumulation. Light west-northwest wind. Alpine low -10C, rising freezing level.FRIDAY: Mainly cloudy with isolated flurries, trace accumulation. Light to moderate west-southwest wind. Alpine high -3C, freezing level rising above 2000 m.

Avalanche Summary

A size 1.5 natural wind slab avalanche was observed in steep terrain on Sunday. Skier traffic produced a few small (size 1) avalanches in the new snow on Thursday.The most recent reports of larger avalanches are from over a week ago, when warm temperatures stressed the deeper layers in the snowpack and produced a few size 2 avalanches.

Snowpack Summary

Strong winds have redistributed snow into thin winds slab in alpine lees and scoured wind-ward areas. In more sheltered alpine terrain and between 1600-2000 m, 5-15 cm recent snow overlies a layer of weak surface hoar and crusts (on solar aspects). Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack has been the culprit for large avalanches in the region over the past few weeks.

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