Avalanche Forecast

Issued: Dec 5th, 2013 7:42AM

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

ccampbell, Avalanche Canada

Cariboos.

This forecast is based on limited field observations. If you head into the mountains, please send a note to forecaster@avalanche.ca and let us know what you saw.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: An arctic ridge of high pressure will persist over the BC Interior and Yukon for the next several days. Friday: Mainly sunny with moderate northerly alpine winds. Treeline temperatures expected to be around -20. Saturday: Mainly sunny with some thin cloud possible, moderate northwesterly alpine winds. Treeline temperatures expected to be around -20. Sunday: Increased cloud, windy, and cold.

Avalanche Summary

No recent avalanches have been reported but incoming field data is still very limited. Avalanche activity in the neighbouring Monashee Mtns seems to be slowing down.

Snowpack Summary

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

Outflow winds are reverse-loading and cross-loading exposed slopes forming fresh and touchy 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: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Dec 6th, 2013 2:00PM