Avalanche forecast

Northwest Coastal

Jan 9 – 10, 2020Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Analyze slopes for patterns of wind effect to navigate around wind slab problems at higher elevations. Remain cautious around steeper slopes at lower elevations where a stubborn storm slab might still release with a human trigger.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2

    Shifting winds have made a big impact on our recent snow accumulations. Strong south to southeast winds accompanied the snowfall and strong northwest winds have been observed in the aftermath. As a result, wind slabs of varying age and reactivity can be found on all aspects at higher elevations. It may still be possible to trigger a storm slab on steeper slopes in sheltered areas at lower elevations

Confidence

Moderate -

Weather Forecast

Wednesday night: Cloudy with scattered flurries beginning in the early morning. Winds shifting from northwest to southwest and increasing from light to moderate.

Thursday: Cloudy with easing flurries bringing 5-10 cm of new snow, finishing during the day and beginning again overnight. Winds shifting back to light to moderate northwest. Alpine high temperatures around -10.

Friday: Cloudy with continuing flurries bringing 5-10 cm of new snow and new snow totals of 20-30cm. Light to moderate southeast winds. Alpine high temperatures around -6.

Saturday: A mix of sun and cloud. Light southwest winds. Alpine high temperatures around -8.

Avalanche Summary

Observations of natural avalanche activity in the region over the past few days showed evidence of storm slabs reaching size 2.5 (large) in the Shames area and the Skeena corridor during the storm.

Similar but more recent wind slabs were also reported, with this activity more pronounced in Bear Pass area where strong outflow winds were recently observed.

Looking forward, our storm snow is expected to form a strong bond with the old surface while our slab problems become increasingly limited to wind-loaded areas.

Snowpack Summary

80-100 cm of recent storm snow has been highly wind affected in the alpine. Expect to find deep wind loaded pockets below ridgetops and in the lee of exposed features. A thin sun crust may exist on steeper sun-exposed slop[es.

This storm snow sits on a crust up to treeline and on extensively wind affected surfaces at treeline and above. 

The underlying snowpack is well consolidated. Two older layers of surface hoar are now buried 130-180 cm deep. The recent widespread natural storm slab avalanche cycle was a good test of these layers, and there have been no reports of avalanches stepping down to them.

Terrain and Travel

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Regions covered