Avalanche Forecast
Issued: Apr 23rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
zryan,
Avalanche Canada
Assess steep alpine features for wind slab before committing to them. Wind slabs will be most reactive where they overlie a firm crust.
Observations are limited at this time of year! Let us know what you're seeing by posting on the Mountain Information Network.
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: Cloudy with a mix of rain and snow, 1 to 5 cm of new snow accumulation at higher elevations. Freezing level dropping to 1000 m. Light to moderate southeasterly winds.
SUNDAY: Cloudy with continued light precipitation. Freezing level rising to 1400 m. Light to moderate southeasterly winds.
MONDAY: Mainly cloudy with light flurries. Freezing level rising to 1400 m. Light easterly winds.
TUESDAY: Mainly cloudy with light flurries. Freezing level rising to 1400 m. Light to moderate northerly winds.
Avalanche Summary
A large cornice failure was observed in the Cleveland riding area on Thursday. The full report can be seen here.
Looking forward to Sunday, fresh and reactive wind slabs are expected to form in lee areas in the alpine and treeline. Wet loose avalanches will be possible at low elevations with rain and warm temperatures. These avalanches will likely be limited to small releases on isolated slopes in extreme terrain.
Reports are limited at this time of year. Please let us know what you're seeing by filling out a MIN report!
Snowpack Summary
New snow and southerly winds are expected to create fresh deposits of wind slab in the alpine and exposed treeline. This 5-10 cm of new snow overlies a faceted and heavily wind-affected surface from last week's strong northerly winds. Large surface hoar has also been found in sheltered areas. On south and west-facing slopes up to 1400 m, a surface crust from spring sunshine can be found, while other aspects hold dry snow. The mid-snowpack is generally strong, overlying weak basal facets at the base of the snowpack.
Check out this MIN report from the Yukon Field Team for a picture of conditions prior to the storm.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Wind slabs are most reactive during their formation.
- Wind slabs may be poorly bonded to the underlying crust.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
New snow and southerly winds are expected to form fresh and reactive wind slabs in lee areas in the alpine and isolated, exposed areas at treeline.
Use caution entering lee terrain features below ridges. The snow could slide easily where it rests on a hard melt-freeze crust, surface hoar, or facetted snow.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices may be weak and reactive to human triggers. They are a significant hazard alone, and may produce large slab avalanches as they fall onto the slope below. Cornice falls are more likely as temperatures warm each day, or when strong sunshine is present.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 24th, 2022 4:00PM
