Avalanche Forecast

Issued: Dec 28th, 2014 7:08AM

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

pgoddard, Avalanche Canada

South Coast.

Good weather for backcountry travel, but stay alert to variable avalanche conditions.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Cold and dry with moderate to strong N-NE outflow winds. A temperature inversion may form on Tuesday/Wednesday.

Avalanche Summary

On Friday, several size 1 avalanches were triggered by snowmobilers below treeline in the Coquihalla area. These are likely to have failed on the mid-December surface hoar layer down about 50cm. On Wednesday skiers reported whumpfing in the Coquihalla area. A week ago, storm slabs up to size 2.5 being remote-triggered from flat areas up to 75 m away in the Coquihalla area between 1600 and 1900 m elevation. Slabs were 40-70 cm thick and were releasing on the mid-December surface hoar layer.

Snowpack Summary

New wind slabs are developing above a layer of buried surface hoar. A deeper layer of surface hoar from mid-December is buried about 60 cm down. The mid-December surface hoar layer is becoming harder to trigger, but snowpack tests are still showing that it has potential for wide propagation. It appears to be most reactive in sheltered treeline locations and may not exist across the entire region. A thick rain crust exists lower in the pack.

Problems

Persistent Slabs

A touchy layer of buried surface hoar crystals has been responsible for numerous small avalanches over the past few days.

Avoid open slopes and convex rolls where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Winds are expected to redistribute recent storm snow into slabs in the lee of ridges and ribs.

Travel on ridgetops to avoid wind slabs on slopes below.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 29th, 2014 2:00PM