Avalanche Forecast

Issued: Dec 30th, 2011 9:35AM

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

triley, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

The snow from Friday should have stopped by Saturday morning, leaving about 10 cm in the Nelson area and closer to 15 cm further south. Saturday should be mostly clear and a bit cooler, but still warm for this time of year. The freezing level is expected to be 700 metres on Saturday, and rising to 1000 metres on Sunday. The next system is forecast to hit the coast on Sunday. High cloud is expected to move in from the Northwest during the day, and may turn to snow by Monday morning. Forecast snow amounts are uncertain for Monday. Some models show the precipitation being confined to the coast.

Avalanche Summary

Natural avalanche activity reported today was limited to a natural wind slab release size 2.5 from an East aspect. We continue to get reports of old activity that occurred during the recent storm.

Snowpack Summary

Height of snow in the Koko Claims area is 120 cm at 200 metres. The mid-december surface hoar is down about 30 cm. The mid-pack is generally well consolidated, and there is a 20 cm layer of 4F facets and depth hoar at the ground. The surface hoar is producing easy to moderate shear test results.

Problems

Wind Slabs

Wind slabs can be found on North-Southeast aspects. Cross-loading is possible on open slopes oriented parallel to the wind. You may find wind slabs further down the slope or on open wind exposed areas below treeline.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Persistent Slabs

Warm temperatures may consolidate the snow above the surface hoar into a slab that may propagate wide avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Dec 31st, 2011 8:00AM