Avalanche Forecast

Issued: Dec 7th, 2013 7:52AM

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

rbuhler, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

The cold arctic ridge of high pressure will persist over the interior regions for the next several days.Sunday: Temperatures around -25C, increasing cloudiness during the day, light snowfall possible, moderate to strong alpine winds from the NorthMonday/Tuesday: A slight warming trend but cold temperatures will persist, mostly cloudy with light snowfall possible, moderate to strong alpine winds from the North

Avalanche Summary

No recent avalanches have been reported but incoming field data is still very limited. Neighbouring regions have had no new reports since Thursday.

Snowpack Summary

Snowpack depths are likely highly variable across the region, with elevation, and in wind-exposed areas. Low-elevation and wind-affected areas likely have a shallow faceted snowpack. While in higher elevation sheltered areas 30-50 cm of recent storm snow overlies a variety of old snow surfaces including surface hoar in sheltered areas and/or sun crust on steep south facing slopes. In some neighbouring areas the buried surface hoar is giving easy to moderate sudden planar compression test results, while elsewhere the storm snow has yet to settle into a sufficiently cohesive slab. There are two distinct weaknesses within the mid and lower snowpack: the early November surface hoar/facet/crust interface is down roughly half way (50-60cm) and the October rain crust is near the ground. Recent snowpack tests gave easy results on the early November mid-pack interface where it was found to be facets under a crust. Cold clear weather is likely promoting surface hoar growth and near surface faceting.

Problems

Wind Slabs

Northerly outflow winds have reverse-loaded and cross-loaded exposed slopes forming wind slabs below ridge crests and behind terrain features. Don't let wind slabs in unusual places catch you by surprise.

Avoid freshly wind loaded features.>Avoid traveling in areas that have been reverse-loaded or cross-loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Managing these persistent slabs can be tricky; they are stubborn and direct evidence of unstable snow may be lacking, but they can produce very destructive avalanches. Treat large open slopes with suspicion until stability is confirmed.

Use extra caution in areas with a thin or variable snowpack.>Use extra caution around convexities or large unsupported slopes.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 8th, 2013 2:00PM