Avalanche Forecast

Issued: Feb 21st, 2018 4:10PM

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

Avalanche Canada pgoddard, Avalanche Canada

Caution if the sun comes out - avoid steep sunny slopes where the snow will lose cohesion.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

THURSDAY: Mix of sun and cloud. Freezing level at valley floor. Light winds.FRIDAY: Light snow (5-10 cm). Freezing level near 600 m. Moderate west to south-westerly winds. SATURDAY: 5 cm snow. Freezing level near 400 m. Light winds.

Avalanche Summary

A widespread wind slab cycle was reported last weekend, with a few naturally and human-triggered size 1-2 avalanches continuing over the last few days. Most of these have been confined to recently built wind slabs, however a couple failed on deeper weak layers in the snowpack, especially when triggered from thin spots on a slope.It will still be possible to trigger a wind slab with the weight of a person in specific terrain. Persistent slabs could still be triggered from thin-to-thick snowpack areas, or with a heavy load. Be mindful of any steep slopes getting cooked by the sun and give these a healthy berth.

Snowpack Summary

You're likely to encounter highly variable snow surfaces after recent strong arctic outflow winds took out their fury on the upper snowpack. Fragile cornices and hard and soft wind slabs can be found on many alpine and treeline slopes. Ongoing cold temperatures are helping to break down and soften these. Windward slopes (roughly north to east facing) have been scoured back to an old crust. The wind slabs sit on various old surfaces including sun crusts, facets and spotty surface hoar (which is most prevalent in sheltered treed locations). Around 50-150 cm down, you'll find a crust/surface hoar layer, which still has the chance to surprise you and could be triggered from a thin snowpack spot, or with a large trigger like cornice fall.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs may be lurking in the lee of ridges and ribs.
Be cautious as you transition into wind affected terrain.Give cornices a wide berth when travelling on or below ridges.Travel on ridgetops to avoid wind slabs on slopes below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 22nd, 2018 2:00PM