Avalanche Forecast

Issued: Apr 11th, 2013 10:53AM

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

jlammers, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Friday: Light snowfall during the day intensifying to moderate in the late afternoon / Moderate to strong southwest winds / Freezing level at 1100mSaturday: Light snowfall / Moderate northwest winds / Freezing level at 1000mSunday: Trace amounts of snow with possible sunny breaks / Light northeast winds / Freezing level at 900m

Avalanche Summary

Observations were extremely limited on Wednesday; however, numerous wet sluffs to size 1.5 were ski cut below 1900m on various aspects. A few naturals of the same size were also observed. I would expect storm slab activity at upper elevations in the wake of Wednesday's storm.

Snowpack Summary

At upper elevations moderate to locally heavy amounts of new snow have been shifted into deeper windslabs by steady southwest winds. About 40-75cm below the surface you are likely to find a temperature/sun crust from last week's clear weather. At the same interface you may find a touchy layer of facets or surface hoar on shaded alpine slopes above ~2400m. Where they exist these weak crystals have been responsible for large remote triggers. The variable and reactive nature of this layer suggests that it may continue to catch people by surprise. At lower elevations (below 1600m) rain has continued to saturate the snowpack. Recent snowfall combined with wind have made large cornices bigger and more likely to fail.

Problems

Storm Slabs

Moderate to heavy snowfall on Wednesday has added to an existing storm/ wind slab problem. Storm slabs may be particularly touchy in wind-affected terrain, or in spots where they overlie weak surface hoar crystals.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 6

Cornices

Recent wind and snowfall has added to size and fragility to existing cornices. Cornice falls may be destructive by themselves, and may also trigger large avalanches on the slope below.

Pay attention to overhead hazards like cornices.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 6

Loose Wet

Rain at lower elevations has promoted ongoing wet snow instabilities. Watch for loose wet avalanches on steep slopes, or glide cracks in terrain with smooth ground cover.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Apr 12th, 2013 2:00PM