Avalanche Forecast

Issued: Apr 12th, 2014 9:13AM

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

jlammers, Avalanche Canada

South Coast.

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

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Sunday: Clear skies / Light and variable winds / Freezing level at about 2200mMonday: Clear with increased cloud late in the day / Light to moderate southwest winds / Freezing level at about 2200mTuesday: Overcast skies with very light precipitation / Light westerly winds / Freezing level at about 1500m

Avalanche Summary

On Saturday a few cornice collapses were reported in a neighboring region including a size 3 release. It is unclear if the cornice release triggered a slab on the slope below. I would expect continued loose wet activity and cornice fall with continued daytime warming on Sunday.In recent days a very large (unknown size) persistent slab avalanche was observed on the northwest face of Mt Matier. The trigger is unknown; however, it demonstrates the potential for destructive persistent slab avalanches. See Wayne Flann's Avalanche Blog for a photo.

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 may still exist, although I suspect they're gaining strength. Surface hoar growth has been noted on shady slopes at higher elevations, and large sagging cornices are becoming weak with daytime warming.The February crust/facet layer is now deeply buried 150 250 cm below the surface. This layer is mostly inactive at this time, but could re-awaken with extended warming, solar influence and large triggers like cornice fall.

Problems

Loose Wet

Watch for loose wet avalanches with daytime warming on steep, sun-exposed slopes. Loose wet avalanches can be pushy and entrain mass quickly.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Cornices

With forecast warming and intense solar radiation the likelihood of triggering a large cornice fall will increase dramatically. A cornice fall may also be what it takes to "wake-up" deep and destructive weaknesses which formed earlier in the season.

Cornices become weak with daytime heating. >Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

Although unlikely, deep persistent avalanches would be very large and highly destructive. Possible triggers include cornice fall, a surface avalanche in motion, warming and intense solar radiation.

Large triggers like cornice fall could initiate a deep persistent slab.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Apr 13th, 2014 2:00PM