Avalanche Forecast

Issued: Feb 5th, 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 and Cornices.

Avalanche Canada ldreier, Avalanche Canada

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Snowfall with moderate westerly wind will increase the avalanche danger throughout the day. Forecast snowfall amounts are uncertain. Make observations and assess conditions continually as you travel.

Summary

Confidence

Low - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday Night: Flurries, accumulation up to 5 cm, moderate to strong northwest wind, alpine high -4 C, freezing level 1200 m. 

Thursday: Snow, accumulation 10-20 cm, moderate westerly wind, alpine high -2 C, freezing level 1200 m.

Friday: Flurries, accumulation 10-15 cm, moderate to strong southwest wind, alpine high -3 C, freezing level 800 m.

Saturday: Mix of sun and clouds, light to moderate northerly wind, alpine high -6 C, freezing level 900 m.

Avalanche Summary

On Tuesday a few small wind slab avalanches (size 1) were observed in isolated lee terrain features. On Sunday there were reports of explosives controlled wind slab and storm slab avalanches to size 2 in the alpine. There was also a report of two size 3-3.5 naturally triggered deep persistent avalanches on a northwest aspects at 2600m. These would have run during or just after the storm on the weekend.

Snowpack Summary

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. Light to moderate amounts of new snow are beginning to obscure this lingering wind effect. Below 1900 m, recent snow overlies a thick crust and tapers quickly with elevation.

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

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • 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 wind from the northwest switching direction to the southwest will load lee terrain features with the new snow. Wind slabs size and sensitivity to triggering will likely increase through the day. 

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices have become noticeably larger and more overhanging in the past week.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 6th, 2020 5:00PM