Avalanche Forecast

Issued: Feb 14th, 2018 5:15PM

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

Avalanche Canada shorton, Avalanche Canada

Wind slabs exist on a wide range of aspects and may be hidden by the most recent snow.

Summary

Confidence

High - on Thursday

Weather Forecast

THURSDAY: Increasing cloud with light flurries in the evening, light to moderate west wind, alpine high temperatures around -10 C.FRIDAY: Trace to 5 cm of new snow by the morning then clearing throughout the day, light northwest wind, freezing level climbing to 1000 m with alpine high temperatures around -6 C.SATURDAY: Moderate snowfall with 10-20 cm throughout the day, strong southwest wind, freezing level up to 900 m with alpine high temperatures around -6 C.

Avalanche Summary

The new snow produced a few small isolated size 1 avalanches on Wednesday. No new avalanches were reported on Tuesday.Some larger wind slabs were reactive to skier triggers on the weekend, including a size 2 avalanche on a north-facing slope near Whistler on Saturday (see MIN report here).Several large cornices have collapsed over the past week. One resulted in a fatal accident in the Callaghan area on Saturday. A snowmobiler was parked 7-10 m back from the edge of a corniced ridge when a large chuck broke off and took the rider down the slope. See here for a full report. A similar incident occurred nearby the same day, but the person only suffered minor injuries. A collapsing cornice also triggered a large slab (size 3) on a north-facing slope west of Pemberton on the weekend. Fragile cornices continue to be a concern in the region.

Snowpack Summary

10-20 cm of new snow sits above a variety of old surfaces, including scoured crusty surfaces on south-facing alpine slopes, old wind slabs on a range of aspects at high elevations, and a melt-freeze crust up to about 1900 m. On average, 180 cm of settled snow now sits on the mid-January crust which generally shows signs of bonding to the overlying snow; however, it has the potential to wake up with a large trigger such as a cornice fall. Below this, the snowpack is thought to be generally strong and well-settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Light amounts of new snow and strong wind has formed new wind slabs and buried older wind slabs on a range of aspects.
Use ridges or ribs to avoid pockets of wind loaded snow.Approach steep lee and cross-loaded slopes with caution.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
Large, looming cornices have formed along ridgelines. They need to be given an extra wide berth from above and below. A large cornice collapse in the wrong location may have the ability to trigger a large avalanche on the slope below.
Falling cornices may trigger large avalanches on the slopes below.Stiff cornices can easily pull back into flat terrain at ridgetop if they fail.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 15th, 2018 2:00PM

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