Avalanche Forecast

Issued: Mar 29th, 2012 10:14AM

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

mpeter, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to variable weather conditions

Weather Forecast

Friday: Expect flurries to taper, yielding a mix of sun and cloud in the afternoon. Winds remain southerly with freezing levels climbing to 1500m. Saturday / Sunday: A weak ridge should keep things dry and relatively sunny with occasional convective flurries and easing southwesterlies until Sunday afternoon, when the next organized system arrives.

Avalanche Summary

Small human triggered windslab events have been reported from lee and crossloaded features at treeline and above. These are isolated to the new storm snow. We also have reports of isolated cornice releases in the high alpine to size 2.0 that did not release deeper layers.

Snowpack Summary

Above 1700m, 25-40cm of new snow now overlies the March 26 interface. This has been accompanied by consistently moderate and at times gusty southerly winds forming windslabs in lee locations. Cornices are huge, and will continue to grow with this weather pattern. The March 26 interface is a crust on all aspects except true north treeline and alpine, where small surface hoar (5mm) is present in sheltered places. The bonds between the new snow and this interface are weak, especially in locations where the surface hoar is present. At lower elevations, the consistent high freezing levels have kept the new snow moist and heavy. Below the newest storm interface, last week's storm snow is well settled and bonded. The deep, persistent early February layers linger in the snowpack and remain a concern with heavy triggers and rapid loading.

Problems

Wind Slabs

New windslabs are forming with the new snow and increased wind. Some interesting thin slabs that formed from previous downflow winds are now lightly buried.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Cornices

Large cornices loom at ridgecrest and will grow under the current conditions. They may act as a large trigger to deeper weaknesses.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 6

Storm Slabs

The new storm snow may become reactive if the sun comes out and heats up the slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Mar 30th, 2012 9:00AM