Avalanche Forecast

Issued: Mar 27th, 2016 8:00AM

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

Parks Canada andrew jones, Parks Canada

Careful evaluation of avalanche problems is still required when traveling above treeline. At lower elevations, avoid slopes with glide cracks.

Summary

Weather Forecast

A weak front tracks across the area today bringing clouds with isolated flurries and trace amounts of accumulation. Alpine high of -2, winds light gusting to 20km/hr and freezing level rising to 1700m. A blocking ridge of high pressure will establish tomorrow, bringing dry and clear conditions with extreme daytime warming by midweek.

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 which provides a good sliding surface. Avalanches may step down to multiple crusts in the top meter. Overnight refreeze created a surface crust at lower elevations that is insulating ~40cm of wet snow.

Avalanche Summary

Warm temperatures brought several small loose wet 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

Freezing levels are uncertain

Problems

Storm Slabs

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Persistent Slabs

An icon showing 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.
If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Minimize exposure to steep, planer south facing Alpine slopes

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Cornices

An icon showing Cornices
Large cornices are an ongoing concern with warmer temperatures. 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 28th, 2016 8:00AM