Avalanche Forecast

Issued: Dec 14th, 2015 8:43AM

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

esharp, Avalanche Canada

Cariboos.

The danger has come down, but large human triggered avalanches remain possible. Start with small test slopes and build up slowly to the bigger terrain features. There is still a lot of uncertainty associated with this early winter snowpack.

Summary

Confidence

Moderate

Weather Forecast

A northwest flow will bring light snowfall, and cool temps throughout the forecast period. TUESDAY: 2-5cm new snow, light northwest winds, -5 at 1500m. WEDNESDAY: Flurries bring up to 2cm of snow, light northwest winds. THURSDAY: Overcast, light northwest winds.

Avalanche Summary

Avalanche activity appears to have tapered off since Friday. Reports from the Columbia Mountains over the weekend detail sluffs in steep terrain, natural slab avalanche up to size 2 failing on a mid-storm instability, and skier controlled avalanche on wind loaded features

Snowpack Summary

Between 80 to 150cm of snow fell last week in the Cariboos. You may find a thin crust about 15 to 50cm below the snow surface as high as 1800m. Below the new snow lies the early December persistent weak layer. This layer may be found as either an old sun crust on south facing features in the alpine, or as large surface hoar and/or small facets in isolated pockets below treeline, especially between 1400m and 1800m. Recent test results on this interface have been widely variable. Sudden planar, resistant planar and sudden collapse results have been reported on the surface hoar as recently as December 13th. Recent winds out of the south have formed wind slabs on lee features that are mainly confined to the alpine, but you may find the odd fresh wind slab at tree-line too. The mid and lower portions of the snowpack are thought to be well settled.

Problems

Wind Slabs

The storm slab problem should be settling out quickly, but I would still be wary of steep unsupported features, slopes immediately lee of ridge crest and convexities.

Start with simple terrain and take a curious/experimental approach to the snowpack. You may be able to step out into challenging and even complex terrain after learning more about the snowpack.>Avoid freshly wind loaded features and use ridges or ribs to sneak around these problem areas.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Persistent Slabs

A layer of buried surface hoar can be found below treeline between 1400m and 1800m. Test profiles suggest this interface varies widely in reactivity indicating that it may still be sensitive to human triggering.

Avoid open slopes, convex rolls, burns, cutblocks and terrain traps when traveling below treeline. This is where buried surface hoar is best preserved and most volatile.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Dec 15th, 2015 2:00PM