Avalanche Forecast

Issued: Dec 28th, 2017 3:52PM

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

jmcbride, Avalanche Canada

Northwest Coastal.

Pockets of reactive wind slab remain a concern for wind-exposed alpine and treeline areas. Watch for stiff or hollow feeling snow and shooting cracks.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY NIGHT: Light snow. Accumulation 2 cm. Ridge wind light southeast. Temperature -20. Freezing level surface.FRIDAY: Mix of sun and cloud. Ridge wind light southeast. Temperature -18. Freezing level surface.SATURDAY: Mostly sunny. Ridge wind moderate northwest. Temperature -18. Freezing level surface.SUNDAY: Mostly sunny. Ridge wind light northwest. Temperature -15. Freezing level surface.

Avalanche Summary

No recent avalanches have been reported. A skier remotely triggered a large wind slab (size 2) near the Shames area on Sunday. The avalanche was triggered on a steep south-facing rocky ridgetop at 1400 m.

Snowpack Summary

Strong outflow winds have affected the surface snow over the past week, scouring some slopes down to an old crust and forming hard deposits in many other areas. Sheltered areas may still have 30 cm of powder from previous storms, but winds have come from a variety of directions and affected much of the terrain. Wind slabs rest on a variety of old surfaces including a thick melt-freeze crust that formed in mid-December. In some sheltered locations, soft feathery surface hoar crystals may sit above this crust.The snowpack is reported to be generally strong below this crust, with the possible exception of areas around Stewart and northern parts of the region where the late-October crust can be found deep in the snowpack. Weak sugary snow may exist around the crust and could be triggered from shallow snowpack areas.

Problems

Wind Slabs

Wind slabs are likely lingering around ridge crests and exposed gullies following the recent outflow wind events. These wind slabs may be poorly bonded to the buried mid-December crust layer and reactive to human triggers such as a skier or rider.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Evaluate unsupported slopes critically.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 29th, 2017 2:00PM