Avalanche Forecast

Issued: Mar 28th, 2016 8:00AM

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

chris gooliaff, Parks Canada

Glacier.

Danger levels will spike with increasing temperatures and the strong March sun beating down on the slopes.

Summary

Weather Forecast

A mix of sun and cloud today with nil precipitation, light northerly ridge-top winds, and freezing levels rising to 1900m. The clouds should dissipate by tomorrow as a ridge of high pressure sits down on the province. Freezing levels will spike well above 2000m by Wednesday as we prepare for the warmth of spring.

Snowpack Summary

~50cm of storm snow combined with sustained SW winds created a slab that is up to 1m deep on lee slopes. This slab overlies a crust on all aspects, providing a good sliding surface. Avalanches may step down to multiple crusts in the top metre. Overnight refreeze created a surface crust at lower elevations that is insulating ~40cm of wet snow.

Avalanche Summary

No new activity observed yesterday. However, warm temperatures over the weekend triggered wet point releases as well as a very large glide crack release (size 3.5). On Friday, a group of 5 accidentally triggered a size 3.0 avalanche on the steep roll on the Thorington line in the Asulkan Valley (NE asp, 2600m, 70m X 100m, 80cm deep on a crust).

Confidence

Due to the number of field observations

Problems

Storm Slabs

A touchy storm slab exists, with 30-50cm over a crust. On lee and cross-loaded features it's up to 1m deep. On Friday skiers easily triggered several size 2's and one size 3. They occurred in predictable places; steep slopes with a convexity.

Choose well supported terrain without convexities.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Persistent Slabs

A series of crusts on solar aspects, buried up to 1.2 m deep, remain a concern. Tests generally take a hard force but continue to produce sudden planar results. This suggests that smaller avalanches, or cornice failures, may trigger large avalanches.

Minimize exposure to steep, planer south facing Alpine slopesIf triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Cornices

Large cornices are an ongoing concern with warmer temperatures and the strong March sunshine. Even small cornice failures can trigger large avalanches.

Extra caution needed around cornices with current conditions.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 29th, 2016 8:00AM