Avalanche Forecast

Issued: Feb 7th, 2020 4:00PM

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

Avalanche Canada ldreier, Avalanche Canada

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Moderate to strong southwest wind overnight will form wind slabs in lee terrain features at treeline and in the alpine. Fresh wind slabs will be sensitive to human triggers especially when exposed to the sun. 

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Friday Night: Snow, accumulation 10-20 cm, moderate to strong southwest wind, alpine high -4 C, freezing level 900 m. 

Saturday: Mostly sunny, light to moderate northeast wind, alpine high -10 C, freezing level 1000 m.

Sunday: Mostly sunny, light to moderate northwest wind, alpine high -6 C, freezing level 900 m.

Monday: Mostly sunny, light to moderate northwest wind, alpine high -3 C, freezing level 1500 m.

Avalanche Summary

On Thursday a few small (size 1) slab and loose dry avalanches were reported. 

On Wednesday several small (size 1) slab avalanches were triggered by explosives and skiers. Several small (size 1) and one large (size 2) loose dry avalanche were reported in the north of the region.

On Tuesday a few small wind slab avalanches (size 1) were observed in isolated lee terrain features.

There was also a report of two size 3-3.5 naturally triggered deep persistent avalanches on a northwest aspect at 2600m. These would have run during or just after the storm on the weekend.

Snowpack Summary

The new snow will be heavily wind affected in the alpine and at treeline after tonight's storm. The fresh snow sits on variable surfaces: Extreme southwest wind leading into last weekend has scoured windward aspects, formed loaded pockets up to 150 cm deep in alpine lees and contributed to rapid cornice growth. Below 1900 m, recent snow overlies a thick crust.

Weak faceted grains and crusts near the base of the snowpack have not been an active avalanche problem recently, despite significant new snow loads. They are still on our radar, especially in inland parts of the region.

Terrain and Travel

  • Be especially cautious as you transition into wind affected terrain.
  • Brief periods of sun could quickly initiate natural avalanche activity.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate to strong southwest wind overnight combined with new snow will continue to form wind slabs throughout the night. These fresh wind slabs will be sensitive to human triggers. Be especially cautious when wind loaded slopes are exposed to the sun. 

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Feb 8th, 2020 5:00PM