Avalanche Forecast

Issued: Feb 2nd, 2013 8:55AM

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

swerner, Avalanche Canada

South Coast.

Summary

Confidence

Good

Weather Forecast

Sunday: The ridge will start to weaken, allowing the next frontal system to move in. Skies will generally be cloudy and no significant precipitation is expected. Ridgetop winds moderate from the West. Alpine temperatures -3.0 and freezing levels around 1300 m. Monday: Back to overcast, grey skies with ridgetop winds blowing light from the SW. Alpine temperatures -4.0 and freezing levels at 1300 m. Tuesday: The next frontal system moves onto the coast. Light snowfall amounts, accompanied by moderate ridgetop winds from the South. Alpine temperatures near -4.0 and freezing levels hovering around 1500 m.

Avalanche Summary

No natural avalanche activity has been reported.

Snowpack Summary

The recent snow seems to be settling and gaining strength although wind slabs may be found on lee slopes (N-SW) behind ridges and ribs and may be touchy to rider triggers. Down 10-30 cm sits a persistent interface comprising of crusts, facets and surface hoar crystals. Recently, this layer has been touchy in sheltered areas at treeline and below (where the surface hoar had a chance to form). Tests done on this layer have produced moderate-sudden planar and resistant planar results and should remain on your radar. Down deeper sits another surface hoar layer (40-80 cm) which seems to be gaining strength with very little reactivity on it.Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in unsupported, shallow, rocky terrain where more faceting has taken place.

Problems

Wind Slabs

New snow has been blown behind terrain features like ridgelines and ribs. The weight of you and/ or your machine may be enough to trigger a wind slab. Cross-loaded features are more suspect due to changing winds.

Avoid freshly wind loaded features.>Use extra caution near lee and cross-loaded terrain near ridge crests.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Buried down 30-60 cm exists a surface hoar/crust/facet layer. This layer of concern seems to be most reactive in sheltered locations over convex rolls and steeper terrain features.

Whumpfing is direct evidence of a buried instability.>Dig down to find and test weak layers before dropping into your run or line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Feb 3rd, 2013 2:00PM