Avalanche Forecast

Issued: Jan 21st, 2013 9:28AM

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

slemieux, Avalanche Canada

Purcells.

Summary

Confidence

Good

Weather Forecast

Monday night and Tuesday: Another day with the upper ridge pattern. Few high clouds with valley clouds above the main valleys, strong Westerlies becoming moderate, the inversion will start to erode and freezing levels also starting to drop. Wednesday: A system coming from the Pacific will begin to affect the region in the afternoon bringing light precipitation, cooler temperatures and lowering freezing level to the surface, with moderate SW winds.Thursday: Lingering precipitation from the system with moderate to strong W winds. Temperatures staying cool.

Avalanche Summary

Numerous loose snow avalanches size 1 were reported on steep solar aspects in the Bugaboos area.

Snowpack Summary

A variety of surfaces await the next snowfall; windslabs in the alpine, facets and surface hoar in localised areas and a suncrust on South facing slopes. The windslabs in the alpine and at treeline are settling and slowly breaking down due to surface facetting. The surface hoar layer below the 40-60 cm of generally well settled snow is still a concern to professionals, especially below 1900 m. in sheltered-shady areas and on S aspects . It still produces sudden planar shears in those areas as well as some resistant planars.Â A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Problems

Wind Slabs

Solar radiation and mild temperatures could weaken some steep S facing slopes and possibly triggering loose wet avalanches.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

A cautious approach is recommended on steep S slopes and sheltered terrain below treeline with forecasted mild temperatures and solar radiation.

Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Jan 22nd, 2013 2:00PM