Avalanche forecast

South Rockies

Jan 27, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Our deep persistent slab problem may grow less likely to trigger in the coming days, but it isn't going away. Maintain diligent, cautious terrain selection that keeps you clear of thin spot trigger points and big overhead hazards.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    Wind continues to redistribute loose snow into wind slabs at higher elevations. Expect to find the deepest and most reactive pockets in immediate lee areas near ridgecrests and around wind-exposed terrain features.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    Deeply buried weak layers are an increasing concern with substantial warming and sun in the forecast. These deep layers are more easily triggered in areas where the snowpack is shallow, such as near ridges and rocky terrain.

Confidence

High -

Weather Forecast

Saturday night: Mainly cloudy. Strong west winds, increasing to extreme in the alpine.Sunday: A mix of sun and cloud. Strong northwest winds easing over the day. Alpine temperatures around -5 and cooling over the day. Freezing level to 1400 metres.Monday: A mix of sun and cloud. Light southwest winds. Alpine high temperatures around -9 with freezing level back to valley bottom.Tuesday: Mainly sunny. Light west winds. Alpine high temperatures around -7.

Avalanche Summary

Recent avalanche observations have been limited to small (size 1), thin slabs released with ski cutting.

Snowpack Summary

Strong winds are stripping the last loose snow available and packing it into thin winds slab in alpine lees and scoured windward areas. Northwest winds have had some of the most recent impact on snow redistribution, creating 'reverse loaded' pockets of wind slab.In sheltered alpine terrain and between 1600-2000 m, 5-15 cm of recent snow overlies a layer of weak surface hoar and crusts (on solar aspects). 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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