Avalanche Forecast

Issued: Dec 12th, 2017 4:20PM

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

Avalanche Canada swerner, Avalanche Canada

Treeline and Alpine elevations are wind hammered. The best snow quality for riding can be found on shady, sheltered slopes.

Summary

Confidence

Moderate - The weather pattern is stable

Weather Forecast

Wednesday: Mainly cloudy. Alpine temperatures plus 3 degrees with the inversion and freezing levels 800 m. Ridgetop winds light to moderate from the southwest. Thursday: Mix of sun and cloud. Freezing levels 1400 m with a weak alpine temperature inversion. Strong ridgetop winds from the southwest.Friday: Mix of sun and cloud. Alpine temperatures near -4 and freezing levels dropping to 900 m. Strong ridgetop winds from the west.

Avalanche Summary

On Monday, a size 2 slab avalanche was reported. At this point we're not sure if it was skier triggered or a natural. The crown depth was 30-50 cm deep by 30 m wide and ran 150 m. The terrain feature was a steep, wind loaded convex roll above treeline in the "Little Simpson" area.Please submit your information to the Mountain Information Network. Give info get info.

Snowpack Summary

Snow surfaces are highly variable throughout the region. Solar and temperature crusts have formed on sun-exposed slopes, while stiff, stubborn wind slabs linger in lee alpine terrain. Feathery surface hoar and surface facets have formed below treeline up to 1500 m. Approximately 30-50 cm of snow now overlies two crusts that were buried near the end of November. These crusts are widespread and extend into the alpine. Although snowpack tests have previously shown hard results at these crust interfaces, more recent observations have been limited. Below these crusts, a well settled mid-pack overlies the late October crust near the base of the snowpack. This "crust/facet combo" layer is widespread and has been reactive to rider and remote triggers. It also continues to produce a variety of resistant to sudden snowpack test results.Average snowpack depths now total 80-140 cm at treeline elevations and up to 160 cm in the alpine.

Problems

Wind Slabs

An icon showing Wind Slabs
Stiff wind slabs may be rider triggered. Watch for triggering in higher elevation, wind-exposed terrain.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The late October crust lies near the base of the snowpack with a thin layer of weak, sugary snow above it. This layer should be on a strengthening trend, but a heavy trigger in a thin snowpack area may still be enough to cause it to react.
Be aware of the possibility for full depth avalanches due to deeply buried weak layers.Be especially cautious in shallow snowpack areas where triggering a deeper layer may be easier.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Dec 13th, 2017 2:00PM