Avalanche Forecast
Issued: Jan 7th, 2021 5:04PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Loose Dry.
Tim Haggarty,
Clear weather revealed a few examples of fresh avalanche activity resulting from the winds and new snow over the last few days. Consider the potential for human triggering as this new snow stabilizes.
Summary
Weather Forecast
A ridge became well established today with mainly clear skies, light winds and near -10 at treeline. Be aware of the potential for an alpine temperature inversion Friday as the ridge persists with little change into the weekend. Expect winds to pick up for Sunday.
Snowpack Summary
5-10 cm on Wed brings recent storm snow totals to 20-50 cm at treeline. This sits on a spotty stellar/surface hoar layer in some sheltered locations. Wind effect in open areas at treeline and in the alpine. Two weak layers from early Dec persist 50-100 cm down. These have been generally unreactive but still giving hard sudden planar results
Avalanche Summary
Evidence of isolated wind slabs up to size 2, 5 to 30cm deep in the last 24- 48hrs resulting from cornice failures and wind-generated sluffs in steep alpine lee terrain. Several loose dry avalanches to size 1.5 were also observed during the day in steep solar terrain. A few of these ran over yesterday's up-tracks in Chickadee slide paths.Â
Confidence
Due to the number of field observations
Problems
Wind Slabs
Strong winds and recent snow have formed wind slabs in lee areas at treeline and in the alpine. We expect natural activity to slow down now that the winds have stopped but the potential for skier triggering may remain elevated in steep terrain.
- Watch for signs of slab formation, such as whumpfing and shooting cracks.
- Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A spotty layer of stellars and surface hoar 25-50 cm down has been reactive in steep terrain. Most likely an issue in steep terrain that was sheltered from previous winds.
2 weak layers from Dec persist and still produce hard sudden planar results
- Dig down to find and test weak layers before committing to a piece of terrain.
- Convex features and steep unsupported slopes will be most prone to triggering.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Loose Dry
The recent snow was failing naturally Thursday on solar terrain. This may persist Friday and may be influenced by a temperature inversion. This would be serious for skiers and climbers in confined features or terrain with associated terrain traps.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 8th, 2021 4:00PM
