Avalanche Forecast

Issued: Jan 21st, 2013 9:20AM

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

South Columbia.

Summary

Confidence

Fair - Timing of incoming weather is uncertain on Wednesday

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 moderate 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

A few natural slab avalanches up to size 2.5 released on steep solar aspect with the exception of one on a NE aspect. Several loose snow avalanches up to size 2 on S facing slopes were also reported. A glide crack release produced a size 2.5 avalanche below treeline on a NE facing slope.

Snowpack Summary

A variety of surfaces await the next snowfall; windslabs in the alpine, facets and surface hoar in specific 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 becoming less of a concern for the professionals but still produces some sudden planar shears amongst other resistant planar and break shears. 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 facing slopes and sheltered terrain below treeline with forecasted mild temperatures and solar radiation.

Watch for glide cracks and give them a wide berth.>Avoid open slopes and convex rolls below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

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