Avalanche Forecast

Issued: Feb 19th, 2020 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Overnight flurries and strong winds will build fresh wind slabs in the alpine and exposed treeline areas. Watch for wind loading around ridgecrests and steep rollovers.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday night: Flurries bringing around 10 cm new snow. Moderate west wind. Alpine low -10 C. Freezing level valley bottom.

Thursday: Mostly cloudy with a chance of isolated flurries late in the day. Moderate to strong southwest wind. Freezing level 800 m.

Friday: Flurries bringing 15-30 cm new snow. Strong southwest wind. Freezing level 800 m.

Saturday: Mostly cloudy with isolated flurries. Moderate south wind. Freezing level 600 m.

Avalanche Summary

Tuesday was a day of varied avalanche activity. Explosive control work produced size 2.5-3 cornices. A natural wind slab size 2 was observed on a southeast aspect and ran to valley bottom in a steep, confined feature. Glide slabs were also observed, where full depth avalanches slid on rock slabs along the highway corridor west of Terrace. 

Loose wet avalanches up to size 2 on steep solar aspects were observed on Monday. A few skier triggered storm slabs size 1-1.5 have been reported, on wind loaded features in the alpine, and running on surface hoar 40 cm deep at treeline.

Snowpack Summary

Overnight snow is being redistributed and loaded into lee features by strong winds at alpine and exposed treeline elevations. At treeline and below, recent snow may sit over patchy surface hoar in wind sheltered areas or crusts on solar aspects.

A thin layer of facets that formed during the January cold snap is now about 120-170 cm below the surface while an early season crust lingers at the base of the snowpack. These layers produced a few large natural avalanches in early February but have recently been unreactive.

Terrain and Travel

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.

Problems

Wind Slabs

An icon showing Wind Slabs

Forecast overnight flurries and strong winds will contribute to new wind slab development. Freshly wind loaded pockets and older deposits that sit over surface hoar will be most reactive to human triggers.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 20th, 2020 5:00PM

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