Avalanche Forecast
Issued: Mar 29th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Cornices.
ahanna,
Avalanche Canada
Storm slabs may remain reactive to human triggers as natural avalanche activity tapers off. Start with small terrain features, look for sign of instability and gather information before considering bigger terrain.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Monday night: Partly cloudy. Moderate to strong northwest wind. Freezing level valley bottom. Alpine temperature -12.
Tuesday: Mostly cloudy. Light westerly wind. Freezing level 1500 m. Alpine temperature -7.
Wednesday: Sunny. Light southwest wind. Freezing level 2100 m. Alpine temperature -1.
Thursday: Mix of sun and cloud. Moderate southwest wind. Freezing level 2100 m. Alpine temperature -1.
Avalanche Summary
Preliminary reports of avalanche activity during the storm include several natural, explosive and skier controlled storm slabs averaging size 1-1.5 in the Monashees and at Revelstoke.
Notable reports of avalanche activity prior to the storm include:
- On Saturday, several natural cornice falls triggered size 2-3 avalanches. One of which is suspected to have run on a deeply buried crust near the base of the snowpack.Â
- On Thursday a natural size 3 was observed on a east aspect at 1800 m in the Valhallas. The crown was 100 cm thick, but no other details are known.
Snowpack Summary
The weekend's storm dropped 20-50 cm over the Selkirk mountains and 10-20 cm in the Monashees. This snow came with wind from southwest to northwest, loading thick slabs in lee features at upper elevations. Reports from Monday have indicated that the new snow is bonding well with underlying surfaces. Crusty and/or moist surfaces exist below treeline depending on elevation and time of day.
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 crusts layer over the past few days.
Terrain and Travel
- Keep in mind that human triggering potential persists as natural avalanching tapers off.
- Start with conservative lines and watch for clues of instability.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Problems
Storm Slabs
Storm slabs may remain reactive to human triggers in wind loaded terrain features. Wind direction has varied from southwest to northwest so watch for these deep pockets on a variety of aspects.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are likely fragile due to rapid growth with recent snow and wind.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 30th, 2021 4:00PM
