Avalanche Forecast

Issued: Apr 15th, 2014 9:24AM

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

Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

Wednesday:Â Mix of sun and cloud. Winds light and variable. Freezing level Â 1800m.Thursday: Light to locally moderate snowfall possible. Â Winds moderate southwest. Freezing level 2300mFriday: Cloudy with sunny periods and scattered flurries. Light west winds. Freezing level 1900m

Avalanche Summary

Reports from the past 2 days include:-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. Three persistent weak layers exist in the highly variable snowpack of the Purcells:-The mid-March sun crust/surface hoar layer down 50-80cm seems to be laying dormant for the time being. -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

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.>Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 8

Valid until: Apr 16th, 2014 2:00PM