Avalanche Forecast
Issued: Feb 24th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
zryan,
Avalanche Canada
Watch for changing conditions. As new snow and wind arrive on Saturday afternoon, fresh reactive wind slabs may form in exposed areas.
Sheltered terrain will offer the best and safest riding.
Summary
Confidence
Avalanche Summary
On Thursday, numerous reports came in of human-triggered size 1 to 2 wind slabs. These slabs occurred on a variety of aspects in the alpine all the way down to below treeline terrain.
Looking forward to Saturday, snowfall and increasing southwesterly winds may form small but reactive wind slabs by the end of the day. Riders should be aware that stiffer and less reactive slabs may linger in lee and cross-loaded areas from previous strong northeasterly winds.
Snowpack Summary
Previous northeasterly winds have redistributed recent storm snow and formed stiff wind slabs in exposed areas. In sheltered areas, surface faceting due to cold temperatures and/or soft surface snow remains.
There are two crusts with facets sitting above, which are buried in the snowpack down 60-180cm in the alpine and treeline elevation bands. These crust/facet layers have been responsible for several large avalanches in the past 2 weeks in the Brandywine and Pemberton Icefield areas.
Weather Summary
Friday night
A mix of sun and cloud. Alpine temperatures around -14 °C. Light ridge wind. Freezing level at valley bottom.
Saturday
Cloudy with snowfall intensifying in the afternoon, up to 5 cm accumulation by end of day. Alpine temperatures reach a high of -9 °C. Mostly light ridge wind occasionally gusting to 40 km/h from the southwest. Freezing level at valley bottom.
Sunday
Flurries tapering in the afternoon, 5-10 cm of accumulation. Alpine temperatures reach a high of -8 °C. Mostly light ridge wind occasionally gusting to 40 km/h from the southwest. Freezing level 800 meters.
Monday
A mix of sun and cloud. Alpine temperatures reach a high of -9 °C. Mostly light ridge wind occasionally gusting to 35 km/h from the southeast. Freezing level 800 meters.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Variable winds have redistributed recent storm snow into stiff pockets of wind slabs. Winds today will be from the southwest, whereas previous wind slabs formed in a reverse loading pattern due to northeast winds. Be sure to assess the snow surface on any aspect you are travelling on for clues of wind effect, like cracking or hollow drum-like sounds.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Two weak layers consisting of a crust with small facets above buried between 50 and 180cm deep, have been responsible for several large avalanches in the past two weeks. This problem seems to be more of an issue west of the Sea to Sky highway corridor. This layer is of greatest concern with large triggers, such as a cornice fall, or by first triggering a smaller avalanche that could step down to this interface.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 25th, 2023 4:00PM
