Avalanche Forecast

Issued: Apr 1st, 2021 4:00PM

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

Avalanche Canada cgarritty, Avalanche Canada

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High elevation north aspects are still offering good skiing and riding conditions, but this is likely where you'll find some overlap with wind slab distribution. Analyze slopes for wind loading patterns and seek out more sheltered, low density snow.

Summary

Confidence

High -

Weather Forecast

Thursday night: Cloudy with isolated flurries. Light to moderate southwest winds.

Friday: Mainly cloudy with isolated flurries, continuing overnight. Light southwest winds. Alpine high temperatures around -2 with freezing levels to 1800 metres.

Saturday: A mix of sun and cloud with cloud increasing. Light to moderate southwest winds, increasing overnight. Alpine high temperatures around 0 with freezing levels to 2000 metres.

Sunday: Cloudy with flurries continuing from the overnight period and 10-20 cm of new snow above about 1700 metres. Light west winds. Alpine high temperatures around -5 with freezing levels to 1600 metres.

Avalanche Summary

Reports from Wednesday showed a trend toward small (size 1) wet loose point releases from steep solar aspects. One larger (size 2), 45 cm-deep storm slab was able to be triggered with a snowcat push in the Selkirks and was noted to have failed on a surface hoar layer from late March. Several more small (size 1) slabs reacted stubbornly to skier traffic and ski cutting on south aspects in the North Columbias. These ran on one of our more recent crust layers.

A widespread natural avalanche cycle occurred during the weekend storm, to size 3-3.5 (very large) in the Selkirks and in the Monashees to size 2.5. Several skier and explosive triggered size 1 wind slabs were reported Monday, and Tuesday. On Tuesday these slabs were reportedly more stubborn to trigger, while small natural dry loose releases were noted occurring in steep terrain at treeline and above. A skier triggered size 2.5 involvement in neighbouring Glacier National Park resulted in lost gear and minor injuries.

Snowpack Summary

Surface crusts exist on solar aspects and below about 2000 metres. Above this elevation, 20-50 cm of recent snow in the Selkirk mountains and 10-20 in the Monashees has otherwise seen some redistribution by southwest to northwest wind, and seems to be bonding well with underlying surfaces.

At alpine and treeline elevations, a few layers of note are buried 50-100 cm deep including a layer of small surface hoar crystals on shady, wind-sheltered aspects and a series of crusts on solar aspects and below 1800 m. Overall the snow seems to be bonding well to these interfaces, although there have been a few isolated avalanches running on deeper crust layers in the past week.

Terrain and Travel

  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Extra caution is needed around cornices under the current conditions.

Problems

Wind Slabs

An icon showing Wind Slabs

Recently formed wind slabs may remain reactive to human triggering in wind loaded terrain features at upper elevations.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Cornices

An icon showing Cornices

Cornices are fragile due to rapid growth from recent snow and wind. Cornice falls are dangerous in their own right and they can also trigger slabs on slopes below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 2nd, 2021 4:00PM

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