Avalanche Forecast
Issued: Mar 31st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Loose Wet.
cgarritty,
Avalanche Canada
Flurries and increasing winds should sustain wind slab problems at high elevations while light rain maintains some potential for wet loose activity lower down. Stay aware of cornices that formed fragile new growth during the storm.
Summary
Confidence
Weather Forecast
Wednesday night: Clearing, becoming cloudy again by morning. Moderate to strong southwest winds, increasing into the morning. Freezing level remaining near 1500 metres.
Thursday: Cloudy with flurries bringing up to 5 cm of new snow, continuing but easing overnight. Moderate to strong southwest winds, easing by evening. Alpine high temperatures around -4 with freezing levels to 1600 metres.
Friday: Cloudy with continuing scattered flurries with up to 5 cm of new snow, continuing overnight. Light southwest winds. Alpine high temperatures around -5 with freezing levels to 1600 metres.
Saturday: Cloudy with continuing scattered flurries and up to 5 cm of new snow. Light to moderate southwest winds. Alpine high temperatures around -2 with freezing levels to 1800 metres.
Avalanche Summary
A natural storm slab avalanche cycle was observed to have run during the storm, widespread size 3-3.5 in the Selkirks and to a more limited extent in the Monashees to size 2, a few of them cornice-triggered. Storm slabs remained reactive to ski cuts on Monday, mostly around size 1 with a couple of skier remotes size 1-2 in the east of the region. By Tuesday, storm slabs were showing signs of becoming more stubborn, showing limited propagation with a few explosive control results around size 2. A skier triggered size 2.5 involvement in neighboring Glacier National Park resulted in lost gear and minor injuries.
Snowpack Summary
Thin new surface crusts have likely formed on solar aspects and below about 2000 metres. Forecast precipitation will likely keep surfaces wet at lower elevations while adding light amounts of dry snow to surfaces above 1500 metres.
20-50 cm of recent snow in the Selkirk mountains and 5-10 cm elsewhere 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 widespread crust exists (except on north-facing slopes above 1800 m) buried 50-100 cm deep. Overall the snow seems to be bonding well at this interface, although there have been a few isolated avalanches running on deeper crust layers over the past few weeks.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Extra caution is needed around cornices under the current conditions.
- Be alert to conditions that change with elevation.
Problems
Wind Slabs
Wind slabs are likely to be reactive in freshly wind loaded terrain features at upper elevations Thursday. Forecast strong winds and light new snow will add to this problem, forming new slabs and obscuring recent ones.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
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, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
A weak overnight refreeze coupled with light rain could maintain wet loose avalanche problems at lower elevations through Thursday. Back off from steep slopes where snow is wet and lacks cohesion.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Apr 1st, 2021 4:00PM
