Avalanche Forecast

Issued: Jan 31st, 2013 8:59AM

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.

triley, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

Overnight and Friday: 3-5 cms expected tonight combined with strong Northwest winds and alpine temperatures about -6.0. Snow ending by morning, becoming high overcast with freezing level rising to about 1100 metres and light Northwest winds.Saturday: Mostly sunny in the South and high overcast in the North with light Southwest winds. Freezing level rising to about 1300 metres. Some areas in the West of the region may experience alpine temperatures above freezing.Sunday: The next Pacific disturbance is expected to move into the interior from the coast. Temperatures should drop below freezing at all elevations before the system arrives.

Avalanche Summary

A couple of cornices were reported to release naturally from North thru East aspects up to size 1.5. Sluffing continues to be reported from steep terrain in wind sheltered areas.

Snowpack Summary

Strong winds have transported snow into wind slabs in the alpine and at treeline. These wind slabs are becoming stiffer and tending to propagate fractures further as they continue to develop. Forecast warm temperatures should settle the recent storm slab, and may make it more reactive where it is sitting above the January 23rd weak layer of facets or surface hoar.

Problems

Wind Slabs

There is a lot of loose dry snow available for transport as the Northwest winds build. Watch for soft wind slabs developing in the lee of terrain features. Cornices may become weak due to warming temperatures, and fall off naturally.

Avoid freshly wind loaded features.>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 - 4

Persistent Slabs

Two surface hoar layers lie buried under the surface, one approximately 40cm down and the other approximately 80cm down. Both are reported to be patchy and variable in distribution. Most likely triggered on steep convex rolls at treeline or below.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 1st, 2013 2:00PM