Avalanche Forecast

Issued: Dec 17th, 2014 7:28AM

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

Avalanche Canada rbuhler, Avalanche Canada

A deeply buried weak layer remains a concern, especially on steep north facing slopes in the alpine. Remote triggering of this layer may still be possible.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The first of two weekend weather systems is expected to reach the interior on Friday. Thursday should generally remain dry with freezing levelsĀ  around 1000m and light to moderate alpine winds from the SW. The Cariboos region may see light scattered flurrries on Friday but it currently looks like the storm will remain to the south. Friday's freezing levels should be around 1000m with moderate alpine winds from the SW. On Saturday freezing levels will rise to around 1500m and alpine winds are expected to be moderate to strong from the SW. Light scattered precipitation is expected on Saturday. The models currently have the second storm system reaching the interior early Sunday.

Avalanche Summary

No new avalanches have been reported since Sunday. On Sunday, snowmobiles remotely triggered a persistent slab with a crown depth around 1.5m in the Allan Creek area. On Saturday, two size 2 remotely triggered persistent slab avalanches were reported. These were triggered from 250m away and released 80-100cm down on the old rain crust from early November. These occurred around 2000-2200m elevation on NW aspects.

Snowpack Summary

A surface crust exists up to around 1800m elevation. Above this elevation is dry storm snow which is settling out and faceting. A new layer of large surface hoar is currently forming on the snow surface. In exposed alpine terrain, strong southerly winds last week may have resulted in variable distribution of the surface snow and the formation of wind slabs. The early November crust/facet layer is down around 1 m in the south of the region, probably less in the north. We received reports that this deep weak layer has resulted in remotely triggered avalanches over the weekend.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The likelihood of triggering a deep persistent slab has decreased but the consequences remain very high. Be wary of any slopes that did not release during the storms. Heavy triggers such cornice falls may be able to trigger a deep weak layer.
Remote triggering is a concern, watch out for adjacent slopes.>Avoid common trigger zones including thin snowpack areas, near rocky outcrops, and steep alpine slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 18th, 2014 2:00PM