Avalanche Forecast
Issued: Dec 15th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
kdevine,
Avalanche Canada
Conservative terrain selection is a good management strategy for a persistent slab problem, as avalanches are typically difficult to predict in these conditions.
Summary
Confidence
Weather Forecast
SUNDAY NIGHT - Mainly cloudy with isolated flurries / southwest wind, 20-30 km/h / alpine low temperature near -10
MONDAY - Flurries, 5-10 cm / southwest wind, 30-60 km/h / alpine high temperature near -5
TUESDAY - Snow, 10-20 cm / southwest wind, 40-70 km/h / alpine high temperature near -3 / freezing level 1200 m
WEDNESDAY - Snow, 10-15 cm / southwest wind, 40-60 km/h / alpine high temperature near -4 / freezing level 800 m
Avalanche Summary
There were a few persistent slab avalanches reported on Saturday, both natural and human triggered, up to size 2.5. Click here to check out a MIN report of a persistent slab avalanche in the Whistler backcountry on Saturday.
On Friday, there were several reports of natural, human and explosives triggered avalanches up to size 2. The majority of these avalanches released on the persistent weak layer that was buried in mid November.
On Thursday, there were several reports of human and explosives triggered avalanches up to size 2. Some of these avalanches stepped down to the persistent weak layer that was buried in mid November.
Snowpack Summary
15-25 cm of recent fresh snow likely sits on a weak layer of surface hoar in some areas, as well as sugary faceted snow.
There is a persistent weak layer from mid November that consists of a crust/facet combination, that is now down approximately 35-70 cm. This layer has been responsible for several recent avalanches. Snowpack tests consistently indicate that this layer can be triggered by humans and propagate widely, resulting in large avalanches.
The snowpack is unusually shallow and weak for the Sea to Sky region. Snowpack depths range between 80-200 cm and taper quickly at lower elevations.
Problems
Persistent Slabs
A persistent weak layer has been responsible for numerous recent avalanches. This scenario is atypical for the sea to sky region, and needs to be treated with caution. The most recent storm is now several days behind us, but the likelihood of human triggered avalanches remains elevated.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 16th, 2019 5:00PM
