Avalanche Forecast

Issued: Apr 14th, 2014 9:41AM

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

mbender, Avalanche Canada

Purcells.

Avalanche danger can rise very quickly with warming and solar radiation. Be aware of changing conditions and overhead hazards.For more insight into spring danger ratings, check out our latest Blog Post.

Summary

Confidence

Good

Weather Forecast

Tuesday: Overcast with isolated snowfall. Winds light to moderate west. Freezing Level 1700m.Wednesday: Overcast with flurries. Winds light and variable. Freezing level 1800m.Thursday: Mix sun and cloud.Winds light to moderate south. Freezing level 2000m.

Avalanche Summary

A natural size 3 cornice triggered avalanche was reported running in the alpine on a north aspect in the central part of the region. The resulting avalanche ran on a steep rocky slope and had a fracture line 3m deep. Another cornice triggered avalanche was reported from the northern part of the region. This was a size 3 on a southeast aspect in the the alpine. The fracture line was 100cm deep running on a suspected crust.

Snowpack Summary

Mainly sunny weather and the freezing level reaching up to 2100m has created moist snow and/or a supportive crust on all aspects and elevations except for high elevation north-facing terrain. This has helped to settle out the past week's storm snow accumulations. Moderate west and northwest winds have redistributed what little dry snow still exists at upper elevations into wind slabs immediately lee of ridge crest.Three persistent weak layers exist in the highly variable snowpack of the Purcells:The mid-March sun crust/surface hoar layer down 50-80cm still has potential for human-triggering in isolated areas. The early-March crust/facet/surface hoar layer down around 80-120cm has become less susceptible to human triggering, but still has the capacity to produce large avalanches.The mid-February crust/facet/surface hoar combo is typically down 60 - 120cm. Direct triggering of this layer has become unlikely, however, cornice fall, a smaller avalanche in motion or prolonged warming may wake this layer up, which would result in very large and destructive avalanches.Weak basal facets exist in many areas, but triggering is unlikely.

Problems

Loose Wet

Expect to see an increase in avalanche activity with forecast rain at lower elevations or on solar aspects if the sun comes out for extended periods of time.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Wind slabs immediately lee of ridge crest and mid slope features may still be sensitive to human triggering.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.>Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Deep Persistent Slabs

Although unlikely to trigger the potential for very large deep slab avalanches needs to remain on your radar. Cornice fall, strong solar, warming temps or a surface avalanche in motion could could act as triggers.

Be aware of the potential for very large, deep and destructive avalanches due to the presence of deeply buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 8

Valid until: Apr 15th, 2014 2:00PM