Avalanche Forecast
Issued: Nov 21st, 2020 8:15AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Storm Slabs.
jonas hoke,
Do not let good visibility and great skiing entice you to ski bigger lines. The Nov. 5th crust/facet persistent weak layer is ripe for catching skiers off guard.
Summary
Weather Forecast
Unsettled air will give mostly cloudy skies and isolated flurries through the weekend. A system making landfall from the NW Monday and will give snowfall early in the week.
Today: Alpine High -8 °C. Ridge wind(RW) light SW. Freezing level (FzL): 1100m.
Tonight: Low -9 °C. RW light S.
Sunday: High -5 °C. RW Light. FzL: 1200m.
Snowpack Summary
Up to 70cm of storm snow and Southwesterly winds has formed reactive slabs. The Nov 5th crust is now down buried over 1m deep in most starting zones. This crust is 8cm thick, and can be found up to 2500m on all aspects. Facets above and below the crust are making this combo an active weak layer that will persist for the foreseeable future.
Avalanche Summary
Large natural avalanches continue to occur as ongoing snowfall and wind progressively overloads the snowpack. These are generally initiating in the storm snow, with some stepping down to the Nov 5th crust/facet combo. There were several Min reports this week of natural, and skier triggered avalanches, as well as large whumphs in open terrain.
Confidence
Problems
Persistent Slabs
Steep open slopes should be avoided. Snowpack tests, and reports of whumphs from yesterday, indicate that this layer could still be triggered by the weight of a skier.
- Be aware of the potential for wide propagations which could result in large avalanches.
- Minimize exposure to overhead avalanche terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Recent new snow and Southwesterly winds have created storm slabs in the alpine, and exposed areas of treeline. Natural avalanches are possible today and skier triggering remains likely, especially on steep unsupported terrain features.
- Convex features and steep unsupported slopes will be most prone to triggering.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 22nd, 2020 8:00AM
