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.
mconlan,
Avalanche Canada
Diligence will be the name of the game for the foreseeable future. A widespread buried weak layer is at a prime depth for human triggering.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
WEDNESDAY NIGHT: Cloudy with snowfall, accumulation 5 cm, 20 to 40 km/h southwest wind, alpine temperature -16 C.
THURSDAY: Cloudy with snowfall, accumulation 2 to 5 cm, 20 to 40 km/h west wind, alpine temperature -12 C.
FRIDAY: Cloudy with snowfall, accumulation 15 to 25 cm, 40 to 60 km/h southwest wind, alpine temperature -7 C.
SATURDAY: Cloudy with snowfall, accumulation 10 to 20 cm, 30 to 50 km/h west wind, alpine temperature -8 C, freezing level rising to 1300 m.
Avalanche Summary
Many storm and wind slabs were triggered by riders and explosives in the recent snow, with most releasing on the surface hoar layer described in the Snowpack Summary. They often occurred between 1700 and 2200 m on east, north, and west aspects.
Similar slabs are expected to be easily triggered by riders where the recent snow sits on surface hoar crystals. Stay diligent!
Snowpack Summary
Around 30 to 60 cm of recent snow overlies a weak lay of surface hoar crystals 5 to 15 mm in size, which is most prominent in areas sheltered from the wind. Example terrain features include the lee side of protected ridges, openings in the trees, cut blocks, and burns. The snow has consolidated and formed storm slabs in some areas, which is expected to remain touchy to riders for some time. In other areas, the snow remains non-cohesive without slab properties, but has the potential to switch at any time. The snow overlies a melt-freeze crust on sun-exposed slopes. Expect to find wind slabs that formed from variable wind directions at higher elevations.
The facet/crust layer that formed in early December is buried around 120 to 250 cm. The last reported avalanche was on January 31 from a large explosive, and before that on January 23. Although unlikely, the layer could be triggered from a large load like a cornice fall or a shallower slab avalanche could step down to this layer. Humans are unlikely to trigger it, with perhaps the exception in thin, shallow snowpack areas. Check out the forecaster blog for more information.
Terrain and Travel
- Good day to make conservative terrain choices.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Make observations and assess conditions continually as you travel.
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Persistent Slabs
30 to 60 cm of snow overlies a widespread weak layer of surface hoar crystals. The layer exists at all elevation bands and has recently been very reactive between 1700 and 2200 m on all aspects except due south, where a hard melt-freeze crust may be found. This layer will remain touchy to riders for some time. If triggered, there is potential that an avalanche could step down to a deeply buried weak layer and form very large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Wind slabs may be found in steep, wind-exposed terrain. They may be found on all aspects due to variable wind directions.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 3rd, 2022 4:00PM
