Avalanche Forecast

Issued: Dec 9th, 2018 3:18PM

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

Avalanche Canada shorton, Avalanche Canada

Snow is on the way this week! Watch for wind slabs forming near ridge crests, roll-overs, and in steep terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

SUNDAY NIGHT: A weak front passes through the region overnight bringing about 5 cm of snow, moderate wind out of the southwest, alpine temperatures drop to -8 C.MONDAY: Light flurries continue throughout the morning with another 5 cm of snow, moderate wind out of the west, alpine high temperatures around -4 C.TUESDAY: The next storm intensifies throughout the day, bringing only trace amounts of snow during the day but then 10-20 cm of snow into the evening, strong wind out of the southwest, alpine high temperatures around -4 C.WEDNESDAY: Mix of sun and cloud with some lingering flurries, strong wind out of the west, alpine high temperatures around -2 C.

Avalanche Summary

Recent avalanche activity was limited to small (size 1) loose dry avalanches that were sensitive to skier traffic in steep terrain.Several small natural wind slab releases were observed in the Whitewater area on Wednesday. These occurred on steep alpine features and may have been a product of recent northerly winds. Big thanks go out to our contributors to the Mountain Information Network. Please continue to post your observations here.

Snowpack Summary

Check out the latest video from Whitewater that summaries their backcountry conditions here. Ongoing cold temperatures and clear skies have formed surface hoar on top of the snowpack and transformed the upper 20 cm of snow into weak sugary snow. At treeline, the height of snow is between 100 and 140 cm. 40 to 80 cm below the surface there is a closely stacked pair of buried persistent weak layers. The upper layer consists of surface hoar (feathery crystals) in most places, but may present as a sun crust on steep south facing slopes. The deeper layer features surface hoar above a widespread temperature crust. Both layers are thought to be widespread at treeline and may also extend into sheltered alpine terrain. These layers are trending towards dormancy, but may remain problematic on steep solar aspects.At the base of the snowpack is a crust that formed near the end of October. Concern for this layer is dwindling but it may still be worth considering in places such as steep rocky terrain, especially where the snowpack is shallow.

Problems

Wind Slabs

An icon showing Wind Slabs
Expect new wind slabs to form in the alpine with the incoming snow and strong wind.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.Use ridges or ribs to avoid pockets of wind loaded snow.Be alert to conditions that change with elevation, aspect and exposure to wind.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Dec 10th, 2018 2:00PM