Avalanche Forecast

Issued: Dec 16th, 2017 6:04PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Freshly formed wind slabs may be sensitive to rider triggering at and above treeline Sunday.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Weather Forecast

At the moment, most of the atmospheric action is on the Northwest Coast. As this system sinks to the south some very light snow and strong wind is expected to impact the southeast corner of the province on Sunday. A secondary system sliding along the border is expected to have more effect on Monday and Tuesday, stay tuned for more details.SUNDAY: Scattered cloud, freezing level at valley bottom rising to around 1000m through the day, moderate southwest wind at treeline, strong northwest wind at ridgetop, trace of snow possible. MONDAY: Broken cloud building through the day, freezing level around 1000m, strong to extreme west/southwest wind, 1 to 5cm of snow possible. TUESDAY: Overcast, freezing level at valley bottom, light variable wind, 5 to 15cm of snow possible. Visit avalanche.ca/weather for a more detailed mountain weather forecast.

Avalanche Summary

On Friday and Saturday small sluffs and soft slab avalanches were reported up to size 1.Please submit your observations to the Mountain Information Network.

Snowpack Summary

Pockets of up to 10cm of new, low density snow now sit on a variety of old snow surfaces that exist throughout the region. Windward slopes have been scoured down to the old rain crust and/or rock. Sun crusts have formed on southerly slopes. In sheltered terrain at and below treeline, very large feathery surface hoar and surface facets (sugary snow) exist. These crystals do not pose a hazard to us now, but once they get buried by new snow they can form a weak layer that may be reactive later. Roughly 30 to 60cm below the surface you'll likely find a hard crust that was buried near the end of November. This crust is approximately 30cm thick and extends from 1600m to mountain top on all aspects. Below this crust, the snowpack is moist to ground. Average snowpack depths at treeline elevations in the region range from 70 to 110cm.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds Sunday will likely continue to form fresh sensitive wind slabs that will be most prevalent immediately below ridge crest and behind mid slope terrain features. While small, these slabs may be problematic in complex terrain.
Use caution in lee areas. Wind loading may have formed new wind slabs.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 17th, 2017 2:00PM

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