Avalanche Forecast

Issued: Feb 1st, 2013 9:18AM

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

triley, Avalanche Canada

Cariboos.

Summary

Confidence

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

Weather Forecast

Overnight and Saturday: Light Northwest winds and thin high cloud overnight with freezing down to the valleys. Light Northwest winds and high cloud with some sunny breaks and the freezing level rising up to about 1300 metres. The Southwest of the region may have some areas of above freezing in the alpine for a couple of hours in the afternoon.Sunday: Freezing levels dropping and alpine temperatures moving down to about -5.0 as the cloud cover thickens in advance of the next pulse of moisture coming from the coast.Monday: Expect a few cms by morning with moderate to strong Westerly winds and continued snow fall during the day.

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.

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.

Watch for wet loose or slab activity with forecast warm temperatures.>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

Cornices

Avoid steep slopes below cornices.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Feb 2nd, 2013 2:00PM