Avalanche Forecast

Issued: Apr 6th, 2013 9:27AM

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

Peter, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Track of incoming weather is uncertain on Sunday

Weather Forecast

Synopsis: A low pressure system is forecast to move through Washington on Sunday, most likely giving cloud and only light precipitation to the South Coast. If it tracks a little further north we could see greater accumulation. A ridge of high pressure should build in later on Sunday resulting in drier conditions and sunny breaks for Monday and Tuesday. Sunday: Mainly cloudy with a chance of flurries. The freezing level is around 1000-1200 m. Winds are easing to light from the northeast. Monday: Sunny breaks. The daytime freezing level rises to around 1500 m. Winds are light from the northwest. Tuesday: Increasing cloud and the possibility of snow late in the day. The freezing level is steady around 1500 m.

Avalanche Summary

Observations are very limited. Continued loose wet activity is likely at lower elevations from recent rain, and the possibility of triggering new wind slabs exists in higher terrain.

Snowpack Summary

Recent snowfall amounts vary depending on location and elevation. Some alpine areas (above 1800-1900 m) could have accumulations of over 30 cm. New dense wind slabs are likely in exposed lee and cross-loaded terrain in the alpine. Most of the recent precipitation has fallen as rain at and below treeline. The upper snowpack at lower elevations has become isothermal from recent warm temperatures. Loose wet sluffs remain a concern below treeline. Cornices are very large and could pop off with continued mild temperatures.

Problems

Wind Slabs

New wind slabs have formed in exposed terrain at higher elevations. Triggering is possible on steep lee slopes and in cross-loaded gullies.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Cornices

Cornices are large and weak and could pop off with additional growth or daytime warming.

Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 6

Loose Wet

Loose wet avalanches are possible in steep terrain during sunny periods, primarily at lower elevations.

Watch for wet loose or slab activity with forecast rain and/or warm temperatures.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 7th, 2013 2:00PM