Avalanche Forecast

Issued: Apr 10th, 2014 9:48AM

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

Avalanche Canada swerner, Avalanche Canada

Avalanche danger can rise very quickly with warming and solar radiation. Be aware of changing conditions and overhead hazards. Terrain choices and timing can be critical.

Summary

Confidence

Good

Weather Forecast

An upper level ridge will keep the region fairly dry and sunny. Solar radiation will be strong, and freezing levels could rise as high as 2500 m by Sunday.Friday: A mix of sun and cloud with isolated flurries. Ridgetop winds light from the West. Freezing levels rising to 1500 m.Saturday: Sunny skies. Alpine temperatures rising to 2.0 degrees. Ridgetop winds moderate from the North. Freezing levels rising to 1500 m.Sunday: Sunny. Alpine temperatures high of 7.0 degrees. Freezing levels rising to 2500 m then dropping overnight. Ridgetop winds light from the SW.

Avalanche Summary

Cornices have started to fail with warmer temperatures and sunny skies up to size 2-2.5, without pulling deeper slabs on the slopes below. Numerous loose wet avalanches occurred up to size 2 on steeper solar aspects.

Snowpack Summary

A melt-freeze crust exists on all aspects up to 2200 m, and dryer snow can be found on high northerly aspects. The recent warmer temperatures have helped to strengthen and settle the upper snowpack, especially on solar aspects. Isolated wind slabs have formed and are sensitive to rider triggers, especially on slopes with a buried crust. Large sagging cornices are looming over slopes and pose a threat, especially when the sun comes out.Snowpack tests are producing moderate shears down 15 cm failing on surface hoar below the early April crust and hard resistant planar shears on the late March crust.Several persistent weak layers exist lower in the snowpack. The mid-March interface down 80 -110 cm, the early-March layer is down about 100-150 cm and the early February layer is now down close to 200 cm. These layers are largely dormant at this time; however, they should remain on your radar as we transition into a warm-up with minimal overnight refreeze and intense solar output.

Problems

Wind Slabs

An icon showing Wind Slabs
SW winds have formed isolated wind slabs on lee slopes. A poor bond may exist, especially on slopes with a buried crust. Rider triggers are possible. Sagging cornices could become weak and fail with warmer temperatures and sunshine.
Use ridges or ribs to avoid pockets of wind loaded snow.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Loose Wet

An icon showing Loose Wet
Warm temperatures and periods of solar radiation will likely make the upper snowpack weak and cohesionless.
Watch for clues and avoid slopes if you start to see pinwheels, moist and/ or wet snow surfaces and natural avalanche activity.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Three buried weak layers exist in the snowpack. Deep releases have become rare; however, the weak layers could be activated by a larger trigger like a cornice fall, or a surface avalanche in motion.
Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Apr 11th, 2014 2:00PM