Avalanche forecast

South Rockies

Jan 28, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Tue
Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low

Highlights

Concern remains for the weak layers that exist near the base of the snowpack. These deep persistent weak layers can be very difficult to manage, so a conservative approach to terrain is recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    Variable wind directions have likely formed wind slabs on all aspects throughout the region. They will likely be most reactive where they sit on a surface hoar layer (sheltered locations).
  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    The bottom of the snowpack consists of weak facets and depth hoar (sugary snow). Triggering this layer is becoming less likely, but the consequences remain high as avalanches on this layer will be very large and destructive.

Avalanche Summary

No new avalanches were reported in the region on Saturday.Previous recent avalanche observations were limited to size 1 thin slabs that released with ski cutting.

Confidence

Moderate - The weather pattern is stable

Weather Forecast

SUNDAY NIGHT - Cloudy with clear periods / northeast winds, 15-20 km/h, gusting to 50 km/h / alpine low temperature near -14 MONDAY - A mix of sun and cloud / light west winds / alpine high temperature near -10TUESDAY - A mix of sun and cloud / light west winds/ alpine high temperature near -6 WEDNESDAY - A mix of sun and cloud / west winds, 10-30 km/h / alpine high temperature near -6

Snowpack Summary

5-15 cm of recent snow overlies a weak layer of sun crusts on south facing slopes, and surface hoar (feathery crystals) in sheltered areas. Strong winds have stripped the new snow off of this layer in wind exposed areas and created deeper deposits in lee features. Wind slabs that have formed over this interface are likely to be more susceptible to human triggers.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 was the culprit in several large avalanches in the region in the past few weeks.

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