Avalanche Forecast
Issued: Nov 22nd, 2020 8:00AM
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/boarders off guard!
Summary
Weather Forecast
A weak ridge passing our area this morning will give some sunny breaks today. A system making landfall from the NW Monday will bring a moderate snowfall Tuesday.
Today: Sunny periods. Alpine High -5 C. Ridge wind (RW) light SW. Freezing level (FzL) 1300m.
Tonight: Isolated flurries. Low -7. RW light S.
Monday: Flurries. High -6. RW Light. FzL 1200m.
Snowpack Summary
Up to 70cm of storm snow over the past week, combined with S'westerly winds, has formed reactive slabs. The Nov 5th crust is now buried over 1m in most starting zones. This crust complex is over 8cm thick, and can be found up to 2500m on all aspects; with facets above and below this is an active weak layer that will persist for a long time.
Avalanche Summary
Large natural avalanches continued early Saturday morning as ongoing snowfall and wind overloaded the snowpack. These were generally initiating in the storm snow, with some stepping down to the Nov 5th crust/facet combo. There were several Min reports last 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, especially at and just above treeline.
Natural avalanches, snowpack tests, reports of whumphing, and near misses in neighboring areas all 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.
- Avoid shallow snowpack areas where triggering is more likely.
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.
Skier triggering remains possible, be especially cautious on steep unsupported terrain features.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- The new snow will require several days to settle and stabilize.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 23rd, 2020 8:00AM
