Avalanche Forecast

Issued: Dec 10th, 2017 3:52PM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs and Loose Wet.

mconlan, Avalanche Canada

South Coast Inland.

Temperature inversion conditions have moistened the snow surface at higher elevations. This is likely on all aspects in the north of the region and predominantly on southerly slopes in the south of the region.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

MONDAY: Clear skies, light southwesterly winds increasing to moderate in the afternoon, freezing level around 3700 m with inversion conditions.TUESDAY: Partly cloudy, light southwesterly winds, freezing level around 2300 m with inversion conditions.WEDNESDAY: Mostly clear skies, light northwesterly winds, freezing level rising to 3500 m over the day with inversion conditions.

Avalanche Summary

Numerous loose wet avalanches up to size 2 were observed on northerly aspects along Duffey Lake Road on Sunday. No new avalanches were observed on Friday or Saturday. Numerous small loose wet avalanches (size 1) were observed on steep south and west-facing slopes on Wednesday and Thursday. Glide avalanches were observed on steep, smooth rock slabs to size 2 around the Coquihalla on Thursday.

Snowpack Summary

Warm air temperatures and sunny skies have created surface crusts on southerly slopes, which may melt with warm air temperatures and under sunny skies.Â North slopes were also affected in areas where cloudy skies prevailed on Sunday, due to the greenhouse effect.Â It appears that this mostly occurred in the northern half of the region.Â For the southern half of the region, northerly slopes likely remained cold.Â Moderate wind speeds from the south may have produced localized wind slabs on northerly lee features. In shady slopes, surface hoar to 20 mm and near-surface faceting have been observed around treeline and in the alpine.Â Cornices may be weakening with the warm air temperatures. The recent snow has formed a strong bond to the late November rain crust, which is now 30-50 cm deep. Treeline snow depths are approximately 1 m throughout the region.

Problems

Wind Slabs

Increased winds from the south may have produced wind slabs, particularly behind ridges in alpine terrain. Be cautious of firm snow when entering lee features.

Avoid wind-loaded pockets near ridges.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Warm air temperatures and clear skies have produced spring-like conditions on steep, sun-exposed slopes. Northerly slopes may also warm up under cloudy skies. Loose wet avalanches may begin small but can grow and push you into dangerous terrain.

Avoid sunny slopes when the solar radiation is strong, especially if the snow is moist or wet.Use caution above cliffs and terrain traps, where small avalanches may have severe consequences.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 11th, 2017 2:00PM