Avalanche Forecast

Issued: Mar 29th, 2013 10:16AM

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

mpeter, Avalanche Canada

South Coast.

Danger could INCREASE TO CONSIDERABLE with intense radiation on south and west aspects, especially at treeline and below. Be aware of how the warm weather is changing the snowpack.

Summary

Confidence

Good

Weather Forecast

Saturday/Sunday: The high pressure system digs deeper! Winds remain light under clear, sunny skies. Alpine temperatures climb to 6 degrees for Sunday afternoon with freezing levels reaching 3000m. It is possible that there will not be a refreeze at treeline and below on Sunday night.Monday: The ridge should begin to break down. Skies will remain clear, light southwesterly winds should begin to blow and alpine temperatures will reach just above freezing.

Avalanche Summary

Loose wet avalanches up to 2.0 have been reported on solar aspects. One size 3.0 wet slab released on the surface hoar crust combo (suspected) from steep terrain (40 degrees) on a south aspect in the low alpine in the last 48hrs.

Snowpack Summary

Recent warm temperatures have created melt freeze crusts up to 2000m on all aspects and to ridgecrest in the alpine on south and west facing terrain. These crusts break down with daytime warming and the surface snow can lose cohesion as a result. Isothermal conditions as deep as 100cm have been reported on South aspects at lower elevations. Cornices are huge!Various melt-freeze crusts are buried in the upper snowpack. In general, the bond at these interfaces is good. A layer of surface hoar (buried on March 11; now down about 60 cm) is still being observed in some locations. Triggering this layer has become less likely, but possible with a large trigger or from a thin snowpack zone. Mid and lower snowpack layers are well bonded.

Problems

Loose Wet

Direct sun and/or daytime warming may cause loose wet avalanches, particularly on steep south and west facing terrain. Wet slabs may also be possible at low elevations where the ground cover is smooth.

Watch for wet loose or slab activity with forecast warm temperatures.>

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 4

Cornices

Cornices are large and become more susceptible to failure due to large temperature fluctuations. This could possibly trigger a slab on slopes below.

Stay well back from cornices.>Be cautious of slopes that are exposed to cornices overhead.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Persistent Slabs

Avalanches failing on a crust and/or surface hoar layer buried about 60cm are unlikely, but could be triggered with a heavy load (cornice), from a thin spot or on a convex slope.

Conditions are generally good, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 6

Valid until: Mar 30th, 2013 2:00PM