Avalanche Forecast

Issued: Feb 20th, 2018 4:17PM

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

Avalanche Canada swerner, Avalanche Canada

The snow is heavily wind-affected. Stick to sheltered trees to find the best and safest riding.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

A fairly benign weather pattern through the forecast period. Wednesday: Mostly cloudy with some sunny periods and a chance of flurries. An alpine high temperature of -13 with generally light westerly winds and some strong gusts. Thursday: Mostly sunny with an alpine high temperature of -7. Ridgetop winds light to moderate from the northeast. Friday: Cloudy with new snow 5-15 cm with the higher accumulations in the south on the Coquihalla. Alpine temperatures near -5 and ridgetop winds moderate with strong gusts from the southwest.

Avalanche Summary

Recently. strong north wind has formed wind slabs at all elevations on southerly slopes. On Monday, natural wind slab avalanches and cornice failures were reported up to size 3. These failed on NE-S aspects above 1800 m. Loose dry sluffing from steeper terrain features was also noted. With little change in the weather forecast natural avalanche activity will subside, but human triggers remain possible.

Snowpack Summary

In sheltered terrain, cold weather is preserving low density snow from the recent storms. In exposed terrain, strong north and east winds have scoured windward slopes and loaded lee slopes. Storm totals from Saturday range from 30 cm in the Duffey area and other northern parts of the region, 50 cm around the Coquihalla, and 40 cm around Manning Park.In southern parts of the region, the new snow sits above a widespread crust with well settled snow below the crust.In northern parts of the region, avalanche professionals are still monitoring the mid-January crust and are avoiding shallow rocky slopes where triggering this layer is most likely. This layer is now 80-150 cm deep, but a heavy trigger (cornice?) or the next major storm (warming and loading) could potentially wake up this layer. Cornice growth has also been reported in northern parts of the region, which could be a potential trigger for an avalanches on the slopes below them.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds from various directions (primarily north and east) have blown recent snow into reactive slabs at higher elevations.
Use ridges or ribs to avoid pockets of wind loaded snow.Approach steep lee and cross-loaded slopes with caution.Pay attention to overhead hazards like cornices which could trigger a slab from the slope below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Feb 21st, 2018 2:00PM