Avalanche Forecast

Issued: Feb 20th, 2018 4:31PM

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

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 is expected through the forecast period. Wednesday: Cloudy with isolated flurries. Alpine temperatures near -12 and ridgetop winds light to moderate from the West.Thursday: Mostly sunny with some cloud cover. Alpine temperatures near -10 and ridgetop winds light to moderate from the North.Friday: Mainly cloudy with some new snow. Alpine temperatures near -9 and ridgetop winds strong from the southwest.

Avalanche Summary

On Monday, numerous wind slabs and cornice failures were reported. Most wind slabs were reactive to rider triggers, and explosive control up to size 2 on all aspects above 1800 m. The cornice failures were triggered by explosives but not pulling a slab or entraining much mass from the slopes below. With little change in the weather forecast natural avalanche activity will subside, but human triggers remain possible.

Snowpack Summary

In exposed terrain, strong north winds have scoured north facing slopes and loaded south facing slopes. In sheltered terrain, especially in the trees the cold weather is preserving 30-40 cm of low density snow. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1900 m, which has supported some wide propagations in recent storm slab avalanches. Deeper in the snowpack, avalanche professionals are still monitoring the mid-January crust. This layer is now 150-200 cm deep, but a heavy trigger (cornice?) or the next major storm (warming and loading) could potentially wake up this layer.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds from the north have blown recent snow into reactive wind slabs at higher elevations.
Use ridges or ribs to avoid pockets of wind loaded snow.Approach steep lee and cross-loaded slopes with caution.Sheltered slopes at lower elevations will offer the best riding.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Cornices

An icon showing Cornices
Large cornices have formed along ridgelines. Cornices are inherently unstable, unpredictable, and demand respect.
Give cornices a wide berth when traveling on or below ridges.Minimize overhead exposure to cornices above, they could trigger a slab from the slope below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

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