Avalanche Forecast
Issued: Dec 8th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
Grant Statham,
Lots of new snow in Little Yoho - 20 cm in Field and at least 30 cm at Emerald Lake settled into a warm, wet slab over surface hoar and crust. Below treeline is tricky now for the first time this winter. Keep it mellow and easy for a few days.
Summary
Weather Forecast
A strong SW flow over continues over the area, although the bulk of the moisture has passed. Expect another 5-10 cm by mid day Wednesday, then a clearing trend and wind following the storm. Temperatures will fall and perhaps even reach -20 by Thursday.
Snowpack Summary
20-30 cm of wet snow has been deposited on top of the Dec 8 layer of surface hoar, sun crust and facets and produces easy test results at the storm snow interface. This indicates a poor bond with the new snow. Over the next 24-hours this snow will settle into a more cohesive slab and the bond will not improve due to the weak layer.
Avalanche Summary
No observations above treeline today, but below treeline in Little Yoho was active with many sluffs and small slabs observed in the Mt Dennis ice climbs, approximately 15-20 cm deep by 2-3 m wide. Watch out on gully walls ice climbers.
Confidence
Problems
Storm Slabs
There is a lot going on with this new snow, so be conservative and observe how it effects the snowpack. We have wind slab up high, storm slabs at and below treeline and lots of loose snow avalanches in cliffs and steep chutes. All on a PWL.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The Nov 5 crust has facets above and below it, and exists up to 2500m on shady aspects and higher on solar aspects. No new observations since the storm, but we expect it may become more reactive with the additional load.
- Be aware of thin areas that may propogate to deeper instabilites.
- Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 9th, 2020 4:00PM
