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 and Cornices.
cgarritty,
Avalanche Canada
A forecast uptick in southwest winds should sustain wind slab problems at high elevations. Stay aware of cornices that formed fragile new growth during the storm.
Summary
Confidence
Moderate -
Weather Forecast
Wednesday night: Clearing. Moderate to strong southwest wind. Freezing level remaining near 1500 metres.
Thursday: A mix of sun and cloud with isolated flurries. Moderate to strong southwest wind, easing overnight. Alpine high temperatures around -2 with freezing levels to 1900 metres.
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. Light to moderate southwest winds. Alpine high temperatures around 0 with freezing levels to 2000 metres.
Avalanche Summary
A widespread natural storm slab avalanche cycle was observed to have run during the storm size 3-3.5 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 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 isolated flurries will add a skiff of dry snow to higher elevations while crusty surfaces below treeline become moist with daily rising freezing levels or light rain.
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
- 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 aspect and elevation.
Problems
Wind Slabs
Wind slabs are most likely to be reactive in freshly wind loaded terrain features at upper elevations on Thursday. Forecast winds may add to this problem, forming small 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.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 1st, 2021 4:00PM
