Avalanche Forecast

Issued: Jan 22nd, 2014 8:40AM

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

jfloyer, Avalanche Canada

Cariboos.

Summary

Confidence

Good

Weather Forecast

A high pressure ridge is once again set to bring dry conditions with warm alpine temperatures.Thursday: Dry. Alpine temperatures initially cool, around -4C, but rising late in the afternoon. Ridgetop winds could feel blustery, up to 40 km/h from the NW in some areas. Friday and Saturday: The inversion is fully in place, with a strong above freezing layer from around 1800 to 3200m. Expect some Valley cloud, that may actually be quite high, and strong alpine sunshine. Alpine temperatures will reach around +5C and will feel higher still in the sunshine. Ridgetop winds 20-30 km/h from the NW.

Avalanche Summary

On Tuesday, two size 2.5 avalanches released on the same slope about 50 m apart. They failed to ground and it is thought that one released naturally and the other released sympathetically in response to the first. These have been the only avalanches reported since Saturday, when a size 2.5 deep persistent slab avalanche was reported to have failed naturally on a southeast facing slope at about 2300m. The avalanche failed on basal facets. On the same day, a snowmobiler triggered what appears to be at least a size 2 slab avalanche form a rocky alpine slope in the Allen Creek area. Little is known about this avalanche.

Snowpack Summary

Snowpack depths vary, but in general there is now 200 to 250cm of snow at tree line and as much as 300 cm in select places in the alpine. In the south and to the east of the region, there are still areas with a relatively thin snowpack. The recent dry, warm weather has generally consolidated the upper snowpack. Old, stubborn hard wind slabs may exist under a skiff of new snow. Steep, sun exposed features are most likely seeing a daily melt-freeze cycle, that could see new snow shed readily, especially where it overlies recently buried surface hoar that lies approximately 10 cm under the surface.A basal facet/crust combo (weak sugary snow above and below a crust) near the ground is still a concern in some areas, and was the culprit with some of the very large recent avalanches. Likely triggers at this interface would include cornice fall, rapid temperature changes or thin spot triggering on an unsupported alpine or treeline elevation slope.

Problems

Wind Slabs

Recent storm snow has set up into mostly thin wind slabs. Caution is required where deposits are deeper.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

Deep persistent activity has lingered longer in this region than in others. Be mindful of thin, rocky areas in steep, convex alpine terrain.

Conditions have greatly improved, but be mindful that deep instabilities are still present.>Avoid convexities or areas with a thin or variable snowpack.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Jan 23rd, 2014 2:00PM