Avalanche Forecast

Issued: Dec 7th, 2017 3:42PM

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

cgarritty, Avalanche Canada

Northwest Coastal.

Cooling temperatures will help to stabilize the snowpack. New surface instabilities should be the main concern on Friday.

Summary

Confidence

Moderate -

Weather Forecast

Friday: Mainly cloudy, with cloud increasing over the day. Scattered wet flurries bringing a trace to 5cm of new snow to high elevations by late afternoon. Light rain below about 1300 metres. Strong south winds. Freezing level to 1800 metres with alpine temperatures around 0.Saturday: Cloudy with periods of wet snow bringing 15-30 cm of new snow to high elevations. Highest accumulations expected in northern and coastal parts of the region. Rain below about 1100 metres. Moderate to strong south winds. Freezing level to about 1600 metres with alpine temperatures of 0 to -1.Sunday: Continuing wet flurries bringing a possible 10-15cm of new snow to only the highest alpine elevations. Rain below about 1800 metres. Moderate to strong south winds. Freezing level to 2300 metres with alpine temperatures of 0 to +1.

Avalanche Summary

No new avalanches have been reported. It is expected that warm alpine temperatures and sunshine initiated natural activity on steep solar aspects at higher elevations on Thursday. Looking forward, we should see diminishing potential for natural activity until a storm pulse brings new snow on Saturday. Please submit your observations to the Mountain Information Network. (MIN)

Snowpack Summary

Snowpack depths in the region range from approximately 140 to 190 cm at treeline elevations. Solar and temperature crusts are expected to have formed on the wind-affected surface at higher elevations on Thursday. A layer of large surface hoar that was recently observed in the Shames area is now buried about 15 cm below the surface. Information on the distribution and reactivity of this layer is limited. Below it, storm snow received over last week is gradually settling above a 5-10 cm thick crust (November 23) down roughly 70-100cm. Another layer of surface hoar (November 11) continues to be observed down approximately 140 cm in the Bear Pass area, showing some signs of improved bonding. The widespread crust/facet interface that was buried at the end of October can now be found 90-160 cm deep. Below it, the basal snowpack is a mix of weaker, sugary snow.

Problems

Wind Slabs

Thin new wind slabs may develop in lee terrain at alpine elevations as new snow begins to arrive along with strong southerly winds. Older wind slabs are expected to have become stubborn, but may still react to heavy triggers in unsupported terrain.

Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Light rain and and wet flurries on Friday may cause small loose wet avalanches to occur, mainly in steep terrain and where moist new snow accumulates.

Use extra caution on slopes if the snow is moist or wet.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 8th, 2017 2:00PM