Avalanche Forecast
Issued: Dec 17th, 2019 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
cgarritty,
Avalanche Canada
Two persistent weak layers are at play in the region, with snowpack tests showing either one could react to a human trigger. Avoid overthinking the snowpack and instead focus on diligent travel practices and conservative terrain selection.
Summary
Confidence
High -
Weather Forecast
TUESDAY NIGHT: Cloudy with isolated flurries and a trace to 5 cm of new snow. Moderate southwest winds.
WEDNESDAY: Mainly cloudy. Light to moderate southwest winds. Alpine high temperatures around -6.
THURSDAY: Cloudy with isolated flurries and a trace of new snow, increasing overnight. Light to moderate southwest winds. Alpine high temperatures around -5.
FRIDAY: Cloudy with continuing snowfall bringing approximately 20 cm of new snow, with new snow totals of 30-40 cm. Precipitation transitioning to rain as high as 1400 metres as temperatures warm over the day to reach around -1 in the alpine. Freezing level rising to about 1600 metres.
Avalanche Summary
Observations from Monday showed only one small new skier-triggered wind slab at 1950 metres in Ymir bowl.
There were reports of a size 1 human triggered avalanche, and natural size 2 avalanche on Saturday that released on the persistent weak layer that is down about 50-60 cm.
Snowpack Summary
Light new snow amounts have buried a thin new layer of surface hoar likely to be found in more sheltered areas.
Including the new snow, collectively 25-35 cm of recent snow sits on another weak layer of surface hoar in many sheltered areas, and on a crust on steep south facing slopes. This layer may be more reactive to human triggers where wind loading has formed a deeper, stiffer slab above it.
Another persistent weak layer found approximately 60-100 cm deep consists of a tightly-spaced series of crusts with sugary faceted snow as well as suface hoar found in between them. This complex layer is more likely to be reactive to human triggers in shallow, rocky areas.
Problems
Persistent Slabs
There are two prominent weak layers in the snowpack right now that are of concern. The first is a layer of surface hoar that was buried last week, and is approximately 25-35 cm deep. The second is a persistent weak layer that is now buried 50-60 cm. Both layers may be reactive to human triggers. Be aware that if the shallower layer is triggered, it may step down to the deeper layer, resulting in a large avalanche.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 18th, 2019 5:00PM
