Avalanche Forecast

Issued: Dec 24th, 2018 3:25PM

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

Avalanche Canada mbender, Avalanche Canada

Looks like a more stable weather pattern for the next few days through Christmas.

Summary

Confidence

High -

Weather Forecast

MONDAY NIGHT: Mostly cloudy with some clear breaks, light  wind, treeline temperature -5,  freezing level in the valley bottom.TUESDAY: Mostly cloudy, light southeast wind, treeline temperature -4 C, freezing level 500 m.WEDNESDAY: Cloudy with isolated flurries, light to moderate southwest winds, treeline temperature -3 C, freezing level 600 m.THURSDAY: Mix of sun and cloud, light west winds, treeline temperature -7 C, freezing level in the valley bottom.

Avalanche Summary

Reports from Sunday indicate several explosive and skier controlled size 1-1.5 storm slab avalanches with a few explosives controlled storm slabs running to size 2, 20-50cm deep.

Snowpack Summary

Around 30 to 40 cm of snow fell during Saturday night and Sunday's storm. The snow fell with southwest winds, likely forming wind slabs in lee terrain features. Below around 1800 m, the snow fell onto a melt-freeze crust formed by rain from Thursday's storm. It may take a bit of time for the new snow to bond to underlying surfaces.A weak layer of facets and surface hoar lies below storm snow, generally around 150 to 200 cm deep. There hasn't been reports of avalanches on this layer for over a week. That being said, this layer may still exist in isolated areas around treeline in some portions of the region.At the base of the snowpack, weak and sugary facets are found below an early-season melt-freeze crust. This weak layer has been the culprit for sporadic, very large avalanches in alpine terrain in the past few weeks. The avalanches have occurred in areas where the ground roughness is very smooth, for example glaciers, firn, and shale/rock slab slopes. An avalanche could be triggered in this layer with a very large trigger, such as a cornice fall.

Problems

Wind Slabs

An icon showing Wind Slabs
The weekend's storm produced new slabs, with the thickest and touchiest likely found in lee terrain features. It is possible that slabs could step down to deeper layers and produce larger avalanches.
Cornices are large and looming near ridges. Give them a wide berth.Use caution in lee areas. Recent wind loading have created wind slabs.Watch for signs of instability such as whumpfing, cracking, or recent avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 25th, 2018 2:00PM

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