Avalanche Forecast

Issued: Dec 23rd, 2015 8:36AM

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

jlammers, Avalanche Canada

Cariboos.

Thanks to everybody who has contributed to the Mountain Information Network! Keep up the great work!

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Expect a mix of sun and cloud for the forecast period, although clear skies may develop for Christmas day. Ridgetop winds should remain mainly light. Alpine temperatures should measure about -15 on Thursday, and then drop to about -20 on Friday and Saturday.

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

20-40cm of low-density snow overlies soft wind slabs which formed last weekend. The few observations we've had suggest a good bond within the storm layers in the upper snowpack. I'd still remain cautious in upper elevation lee terrain where buried wind slabs may still be sensitive to human triggering. Between 80 and 130cm below the surface you'll likely find a weak layer of well-developed surface hoar which was buried in early December. This layer is most widespread at lower elevations (between 1100m and 1700m.) Snow pit tests suggest that human triggering of this interface has become less likely. That said, if it does fail the overlying slab is stiff enough to propagate over a wide distance. Below this layer, the snowpack is thought to be generally strong and well-settled.

Problems

Wind Slabs

Low-density powder may be hiding wind slabs which formed during stormy weather on the weekend. They may have gained considerable strength, but I'd remain cautious on high-elevation lee slopes. Loose dry avalanches are also possible in steep terrain.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A layer of buried surface hoar can be found between 1100m and 1800m. Although this layer has become less likely to trigger, I'd remain cautious on steep roles in cut-blocks and open glades below treeline.

Avoid steep open slopes, convex rolls, burns, cutblocks and terrain traps when traveling below treeline. >Conditions are greatly improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 24th, 2015 2:00PM