Avalanche Forecast
Issued: Feb 23rd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
jcoulter,
Avalanche Canada
Pockets of wind slab likely linger on various aspects in exposed terrain and around ridgelines.
There is recent evidence that the persistent avalanche problem can still be human triggered in parts of the region.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast. Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
WEDNESDAY NIGHT: Trace of snow possible, light westerly winds. Alpine low of -16.Â
THURSDAY: Mix of sun and cloud, light northerly winds and alpine high of -7.
FRIDAY: Partly cloudy, light westerly wind and high of -8.
SATURDAY: Mostly sunny, moderate southwest winds, alpine high of -4.
Avalanche Summary
On Tuesday a backcountry user near Whitewater was able to trigger small wind slabs near ridgecrest and found better riding in lower, more sheltered terrain. Explosives control in the region was able to trigger wind slab avalanches in the size 1.5 range. On Monday there were several size 1-1.5 wind slabs triggered by skiers as well as a few natural wind slabs spotted in the backcountry. Surface hoar layers buried in January have also been implicated in two recent size 2 avalanches in the region.Â
Snowpack Summary
Recent northeast winds have scoured and wind-affected open areas forming wind slabs in lee terrain. This reverse loading means there may be wind slabs in unusual places. In sheltered locations, there is likely around 20-40 cm of snow over an old February drought layer interface that consists of various melt-freeze crusts and old wind-pressed snow depending on your elevation and aspect.
Two layers of buried surface hoar sit in the upper snowpack and are likely most reactive in sheltered areas at treeline. These are now down around 40-50 cm and 50-70 cm deep. Though improving, these layers remain reactive in some snowpack tests and have been responsible for sporadic avalanches, including a recent size 2 that was triggered remotely by a skier walking on a ridge.
The lower snowpack is well consolidated, with a crust/facet layer found 100 to 200 cm deep. It is currently considered dormant, but could become active later this season. Check out the forecaster blog for more information.Â
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
Problems
Wind Slabs
Watch for pockets of wind slab on various aspects in exposed terrain and around ridgelines. Recent northeast winds have reverse loaded features building slabs in less common places.
These slabs have formed on top of old crusts and hard wind-pressed snow and there is uncertainty about how quickly they will bond to old surfaces.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Surface hoar layers buried in January have been implicated in two recent size 2 avalanches in the region. Various combinations of crusts above and below these layers have made the distribution and sensitivity of this problem difficult to pin down.
Be cautious on steep open slopes around treeline where these layers are most likely to have been preserved and linger.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 24th, 2022 4:00PM
