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
Snow returns briefly on Friday, before conditions warm and skies clear into the weekend.
WEDNESDAY NIGHT: Cloudy. Moderate westerly winds. Freezing level at valley bottom. Isolated flurries possible.
THURSDAY: Cloudy with sunny breaks. Moderate to strong westerly winds. Freezing level at valley bottom. Alpine high -9.
FRIDAY: Cloudy with 5 -10 cm of snow . Strong westerly winds, gusty around ridge top. Freezing level 1000 m, alpine high of -5.
SATURDAY: A mix of sun and cloud with chance of flurries. Moderate to strong westerly winds. Freezing levels around 1500 m, alpine high of -3.
Avalanche Summary
The recent storm produced a natural avalanche cycle to size 2.5 with activity observed on Monday and Tuesday. Storm slabs and were also triggered by ski cutting and explosives to size 2 on Monday.
Shooting cracks and whumpfing have been reported by industry operators and in several MIN reports. This indicates the buried surface hoar layer is sensitive to human triggers.
On Monday, a size 2.5 natural persistent slab avalanche was reported to have occurred on a path that had previously avalanched where storm snow reloaded bed the surface.
Snowpack Summary
At lower elevations up to 30cm 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 by moderate to strong westerly winds. A thin melt freeze crust extends into the alpine on solar aspects. This crust may sit on the surface or below wind deposited snow.
The widespread January 18 rain crust is now around 40-50 cm deep with weak faceted snow above, however it has not been producing avalanches recently.
The early December crust/facet persistent weak layer is now 100-200 cm deep. 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.
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.
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
