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 Persistent Slabs and Wind Slabs.
wlewis,
Avalanche Canada
Wind slabs may continue to build in exposed terrain. Check for freshly wind loaded features as you gain elevation.
Wind sheltered terrain will have the best snow, but be cautious of open slopes at treeline and below. Buried surface hoar may be sensitive to human triggering.
Summary
Confidence
Weather Forecast
A chance of snow returns briefly on Friday, before conditions warm and skies clear into the weekend.
WEDNESDAY NIGHT: Mostly clear. Moderate westerly winds. Freezing level at valley bottom. Isolated flurries possible.
THURSDAY: A mix of sun and cloud. Moderate westerly winds with strong gusts. Freezing level at valley bottom. Alpine high of -9.
FRIDAY: Cloudy with flurries bringing up to 5cm by the end of the day. Moderate westerly winds with strong gusts. Freezing level rises to 1200 m. Alpine high of -5.
SATURDAY: A mix of sun and cloud with moderate westerly winds. Freezing levels rise around 1500 m, with alpine highs of -3. Moderate westerly winds.
Avalanche Summary
The recent storm produced a natural avalanche cycle to size 2. Small storm slabs and loose dry avalanches were also triggered by ski cutting and explosives on Monday.
Shooting cracks and whumpfing have been reported by industry operators and in several MIN reports. This indicates the surface hoar is sensitive to human triggers.
Snowpack Summary
At lower elevations 20-40 cm of storm snow sits over a thick melt freeze crust. In sheltered terrain, a layer of large surface hoar crystals may sit immediately above the crust, sensitive to human triggers.
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 areas.
The early December crust/facet persistent weak layer is now 100-200 cm deep. This layer produced numerous very 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.
Terrain and Travel
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- 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.
Problems
Persistent Slabs
Fresh snow sits over a large and sensitive surface hoar layer. Treat open slopes at treeline and below with caution - they may be more reactive and produce larger avalanches than you expect. Watch for signs of instability as you travel, like shooting cracks and whumpfing.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
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
