Avalanche forecast

South Coast Inland

Jan 24, 2017Avalanche Canada
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Archived · expired 10 years ago

Avalanche danger

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

Keep your objectives in check as stability improves. Wind slabs are distributed widely and a weak layer still exists below our new snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Weaknesses exist within and under the new snow. Slabs will be particulary deep and touchy on wind-loaded aspects near ridge crests. Keep in mind the possibility for a wind slab avalanche to "step down" to the weak layer below our new snow.

Confidence

High - The weather pattern is stable

Weather Forecast

Tuesday: Cloudy with sunny periods and no new snow. Winds light from the northwest. Freezing levels ranging from 800 to 1200 metres with alpine temperatures to -6. Wednesday: Mainly cloudy. Winds light from the southwest. Freezing levels around 700 metres with alpine temperatures around -7. Thursday: Mainly cloudy. Winds light from the southwest. Freezing levels about 900 metres with alpine temperatures of -2.

Avalanche Summary

Reports from Sunday included an impressive natural avalanche cycle observed in the South Chilcotin, where three Size 2.5-3 avalanches occurred on adjacent southwest-facing slide paths within 2 hours of each other. The crown fractures averaged a metre in depth and all initiated at treeline elevation. Direct sunlight was determined to be the trigger of these slides.

Snowpack Summary

SOUTHERN AREAS (e.g. Coquihalla): 10-20cm of snow from last week appears to be bonding well to the previous rain-soaked snow surface up to treeline elevations. At alpine elevations, up to 40cm of storm snow fell with some wind slabs forming on northerly aspects.NORTHERN AREAS (e.g. Duffey Lake): Up to 45 cm of fresh snow by Friday morning brought the storm snow totals to over a metre, which was all redistributed by moderate to strong southerly winds. This resulted in touchy storm and wind slabs bonding poorly to the previous snow surface that includes facets and large surface hoar on sheltered slopes and/or a sun crust on steep sun-exposed aspects, as well as wind-affected surfaces (e.g. hard wind slab, sastrugi, scoured crust, etc.) in exposed areas. Weaknesses within the recent storm snow have been settling - I'd remain suspicious of the bond of the storm snow in the alpine to the previous cold snow surface from over a week ago.

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