Avalanche Forecast
Issued: Feb 2nd, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Wind slabs continue to be a concern, watch for freshly wind loaded terrain features at higher elevations.
Wind sheltered terrain will have the best snow, but be aware of open slopes at treeline and below where new snow sits over surface hoar.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Snow returns briefly on Friday, before conditions warm and skies clear into the weekend.
WEDNESDAY NIGHT: Some cloud, moderate to strong westerly winds. Chance of flurries. Freezing level at valley bottom. Alpine high -15.
THURSDAY: A mix of sun and cloud, moderate to strong northwest winds. Freezing level at valley bottom. Alpine high -10. Isolated flurries.Â
FRIDAY: Cloudy, with up to 5 cm expected, favouring the north. Moderate to strong westerly winds. Freezing level around 500 m. Alpine high of -5.Â
SATURDAY: Another 5cm by Saturday morning is possible with continued strong westerly winds. A mix of sun and cloud. Freezing level rises towards 1500 m. High of -5.Â
Avalanche Summary
Loose dry avalanches to size 1.5 were naturally and human triggered in steep terrain features yesterday.Â
Natural wind slabs to size 2 were observed to occur in exposed alpine features during rapid wind loading from strong westerly winds yesterday.Â
Snowpack Summary
At lower elevations, 20-40 cm of storm snow sits over a melt freeze crust. In sheltered terrain a widespread layer of large surface hoar crystals sits immediately above the crust, which may be sensitive to human triggers.Â
At higher elevations the storm snow has been redistributed into pockets of wind slab by strong westerly winds. A thin melt freeze crust extends into the alpine on solar aspects. This crust may sit on the surface in exposed terrain, or below wind deposited snow in sheltered features.Â
Several surface hoar layers are now buried in the upper snowpack 30-60cm deep. The early December crust/facet layer of concern sits around 80 cm deep in the eastern Purcells and shallow terrain, and up to 150 cm in the west. This layer produced numerous large avalanches in January, and is now considered dormant. We will continue to track this layer of concern and expect it will wake up again with major warming or a large storm event. This recent forecaster blog goes into more details on the layer and how to manage it.Â
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Be alert to conditions that change with elevation and wind exposure.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Problems
Wind Slabs
Fresh wind slabs may build with continued strong westerly winds. Expect reactivity where they overly a smooth crust, or a weak surface hoar layer in sheltered terrain features.
Expect wind loading in unusual places, as wind direction is atypical and stronger wind speeds may load mid slope features.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 3rd, 2022 4:00PM
