Avalanche forecast

South Coast Inland

Feb 11, 2017Avalanche Canada
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Avalanche danger

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

Human triggered avalanches remain likely on Saturday at treeline and above. Use small slopes with low consequence to test the bond of the storm snow.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    This problem is more prevalent in the far north areas of the region and is a low likelihood, high consequence scenario that will need to be monitored as snow loads increase.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Continued snow and wind are making the existing storm slabs increasingly dangerous.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Seasonal temperatures and isolated flurries through the weekend. Significant warming Monday onwards. SATURDAY: 15-20cm possible for the Coquihalla and Duffey zones by Saturday morning. Mostly cloudy with isolated flurries. / Light to moderate southwesterly winds/ Freezing level around 900 m / Alpine highs to -7 Celsius SUNDAY: Cloudy with sunny breaks / Light, southwesterly winds / Freezing level rising to 1400 m in the afternoon. MONDAY: Sunny with cloudy periods, warming significantly with highs to +1 Celsius / Moderate southwesterly winds / Freezing level around 2000 m.

Avalanche Summary

A widespread natural avalanche cycle (to Size 2.5) occurred on all aspects and elevations at treeline and above from Thursday into Friday. 

Snowpack Summary

An additional 40+ cm of snow on Thursday added to the 35-50 cm (lower amounts in the north) of recent storm snow. Temperatures rose on Thursday afternoon, increasing the likelihood slab avalanches with the heavier snow on top of lighter, drier snow. All this storm snow is sitting on a wide variety of old snow surfaces including stiff wind slab or wind effected snow at upper elevations, sun crust on steep southerly slopes, surface hoar and surface facets in sheltered locations. The mid-January surface hoar and facet interface is now buried 90-120 cm and the mid-December facets down 130-160 cm still remain a concern especially in shallower snowpack areas in the Duffey, Hurley and/ or South Chilcotins. These deeper weaknesses warrant monitoring, especially through periods of rapid loading. In southern areas (Coquihalla), the lower snowpack is reportedly well settled (stronger), than it is to the north.

Regions covered