Avalanche forecast

South Coast Inland

Dec 24, 2017Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Similar but different!Hazard ratings are for the southern part of the region where storm snow totals range from 80-100 cm. Northern areas that received less snow can expect the same problems but a lower hazard rating.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Outflow (northerly) winds have redistributed the recent storm snow scouring windward areas and building wind slabs on leeward slopes and exposed areas. These slabs sit on the recent crust and may be reactive to light loads such as a skier or rider.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    It may be possible to trigger a storm snow release on steep or convex terrain in areas sheltered from the wind.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SUNDAY: Cloudy, flurries. Accumulation 2-5 cm. Ridge wind moderate from the west. Temperature -9. Freezing level surface. Strong outflow winds near coastal valleys.MONDAY: Mostly cloudy, flurries. Accumulation trace. Ridge wind light from the north. Temperature -9. Freezing level surface.TUESDAY: Mostly sunny. Ridge wind light. Temperature -10. Freezing level surface.

Avalanche Summary

There were no new reports of avalanches on Thursday although whumpfing in hard wind slabs on cross-loaded features at treeline was observed in the northern part of the region. On Wednesday the Coquihalla and Allison Pass areas saw numerous loose dry to Size 1.5, as well as slab and glide avalanches to Size 2 on steep, leeward terrain and smooth rock slabs. Reports from the northern part of the region indicated wind slab activity up to size 2 on north and west aspects in the alpine.In the southern part of the region classic signs of instability such as whumpfing and shooting cracks have also been reported here in the MIN.

Snowpack Summary

The recent storm snow has been redistributed by moderate to strong northerly winds in the alpine and exposed treeline areas, creating wind slabs in some areas and scouring others (particularly in the northern part of the region).The southern part of the region has seen impressive storm snow totals (80-100cm) since Sunday night, compared to northern areas of the region, which received 25-35cm. This new snow sits on crusts of variable thickness that formed on almost all aspects in mid-December (December 15th layer). On steep southerly aspects the crust is supportive, whereas on northerly aspects the crust is quite thin and variable. Beneath the December 15th layer the snowpack is well settled. The late November rain crust is now buried 50-80 cm in the northern part of the region and well over 1 m in the south. Great conditions reports from the north of the region on the Mountain Information Network (MIN) here, as well as from the southern part of the region, here.

Regions covered