Avalanche Forecast

Issued: Dec 20th, 2014 3:00PM

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

Avalanche Canada jlammers, Avalanche Canada

Generally light amounts of new snow are expected on Saturday night. If more snow falls, consider these danger ratings to be too low.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

A weak storm is expected to start on Saturday evening and persist into Sunday bringing only light amounts to this region. Current models are showing around 5 cm from 4pm Saturday to 4am Sunday with another 2 cm or so on Sunday. Freezing levels are expected to be around 1600 m on Saturday and then rise to around 1800 m on Sunday. Winds are expected to be around 60 km/h from the southwest overnight Saturday and into Sunday. Monday looks mostly dry with northwest winds and freezing levels around 1500 m. By late Tuesday, the pattern should change again as another pacific system tracks across the south of the province bringing light to moderate snowfall and elevated freezing levels.

Avalanche Summary

Size 1 storm slabs were triggered by explosives and ski cutting on Friday. With weather forecast for Saturday night, further avalanche activity of this nature is expected.

Snowpack Summary

Surface hoar has grown on top of 10-20 cm loose dry snow that has been sluffing readily on a thick hard supportive rain crust that extends into alpine elevations. In the alpine, winds have been conducive to blowing this low density snow into thin wind slabs in exposed lee areas. At treeline and below, the near surface crust is effectively bridging triggers from penetrating to deeper persistent weaknesses that formed earlier in the season. However, on alpine slopes above the recent rain line poorly bonded crusts, facets, and/or buried surface hoar may be susceptible to triggers. Professionals are still concerned with a buried crust from November, down 50-70 cm, that could be triggered by large loads.

Problems

Wind Slabs

An icon showing Wind Slabs
Generally light amounts of new snow are expected on Saturday night, but extreme winds are expected to shift this snow into pockets of wind slab in exposed terrain. Watch for wind slabs in gullies and in the lee of ridges.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 21st, 2014 2:00PM

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