Avalanche Forecast
Issued: Feb 28th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
ahanna,
Avalanche Canada
A bit of new snow with strong wind will keep wind slabs fresh Monday. Keep an eye out for wind affected snow on atypical aspects and lower-than-usual elevations due to recent variable wind direction and elevation.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Sunday night: Light flurries bringing a trace of snow. Freezing level 1100 m. Strong southwest wind affecting all elevations.
Monday: 5-10 cm new snow. Freezing level 1400 m. Strong southwesterly wind affecting all elevations.
Tuesday: Around 5 cm overnight then clearing. Freezing level 700 m. Light to moderate southwesterly wind.
Wednesday: Mix of sun and cloud. Freezing level 1300 m. Light to moderate southwesterly wind.
Avalanche Summary
By Saturday, reports of natural and human triggered avalanche activity quieted down but cornices continued to be reactive to explosives size 2-2.5. Minor pinwheeling was observed on steep solar aspects in the afternoon. On Friday, storm/wind slabs were reactive to human triggers around treeline to size 1. A natural avalanche cycle up to size 3 occurred during the storm on Thursday, primarily on north to east aspects 1500 to 2000 m.
Snowpack Summary
20 cm of recent snow overlies a variety of old surfaces including facets, spotty surface hoar in wind sheltered areas around treeline, a sun crust on steep solar aspects and a rain crust below 1500 m. Upper level wind, having recently shifted northwest is likely transporting the recent snow into wind slabs in a reverse-loading pattern in exposed features at upper elevations. Older wind slabs formed by previous southwest winds may also remain reactive to human triggers.
Another weak layer buried in mid-February is composed of a crust, facets or spotty surface hoar depending on elevation/aspect, and is now down 50-80 cm. There have been no recent avalanches reported on this layer. Large triggers, such as an avalanche in motion, cornice fall, or intense loading from snow, wind and/or a rapid rise in temperature could awaken these deeper weak layers.
The mid and lower snowpack is well settled and strong in most areas.
Terrain and Travel
- Keep your guard up at lower elevations. Wind slab formation has been extensive.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Minimize your exposure time below cornices.
Problems
Wind Slabs
Strong winds may spill over into low elevations Sunday night and Monday so watch for freshly wind affected snow lower down on the mountain than usual. Recent wind has varied in direction so wind slabs may be found on all aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large, looming, and require extra caution under the current conditions.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 1st, 2021 4:00PM
