Avalanche Forecast

Issued: Dec 10th, 2018 4:58PM

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

Avalanche Canada jfloyer, Avalanche Canada

Avalanche danger will be driven mostly by the wind, as snow amounts gradually accumulate this week.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

Monday Night: Only trace amounts of new snow expected overnight.Tuesday: 5-10 cm new snow expected with moderate southwesterly winds. Freezing level rising to around 600 m at the end of the day.Wednesday: Flurries. Moderate northwesterly winds. Freezing level around 1200 m.Thursday: Light snow, 2-4 cm. Strong southwesterly winds. Freezing level rising to around 1400 m.

Avalanche Summary

Several size 1.5 natural wind slab avalanches were reported from a steep south through southwest facing alpine feature on Friday.

Snowpack Summary

Light amount of new snow and recent winds have created wind slabs in the alpine and isolated treeline areas. Incoming new snow will likely not bond well on account of the faceted (sugary) nature of the upper snowpack.There are two layers of surface hoar (weak feathery crystals) being reported in the top 15-30cm. The surface hoar is most prominent at treeline, but it may be found in sheltered alpine areas. Both of these layers may be associated with a sun crust on south aspects in some areas.Another major feature in the snowpack is a combination of a crust and faceted (sugary) snow found at or near the base of the snowpack. This layer is most prominent in the alpine.The early season snowpack is highly variable in the Purcells. Total snowpack depths vary greatly throughout the region with anywhere between 70 and 150 cm in the alpine tapering rapidly at treeline and below. In shallow snowpack areas, the bottom half of the snowpack is reportedly weak and "hollow" feeling on shady aspects due to sugary, faceted snow.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong southwest winds and light snowfall are expected to form thin new wind slabs in the alpine.
Watch for newly formed wind slabs around leeward slopes and features in wind affected terrain.Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 1.5

Valid until: Dec 11th, 2018 2:00PM