Avalanche Forecast
Issued: Dec 27th, 2018 3:32PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
dsaly,
Avalanche Canada
Persistent slabs are tricky to manage. Avalanche activity is receding, but if triggered, an avalanche falling on the persistent weak layer could have serious consequences. Read the latest Forecaster Blog on the persistent slab problem here.
Summary
Confidence
Low - Due to the number of field observations
Weather Forecast
THURSDAY NIGHT: Cloudy with clear periods. Light northwest wind. Alpine low -13C.FRIDAY: Mix of sun and cloud. Light increasing to moderate west wind. Alpine high of -11C.SATURDAY: Cloudy with scattered flurries, trace to 10 cm accumulation. Moderate west wind. Freezing level rising above 1200 m.SUNDAY: Mix of sun and cloud. Light northwest wind with occasional moderate-strong gusts. Alpine high -8C.
Avalanche Summary
The persistent weak layer was active last weekend, explosives triggered avalanches to size 2.5 and a cornice triggered a size 2 avalanche. Skier traffic was also able to trigger wind slab avalanches to size 2. Information in this region is limited. Post your observations to the Mountain Information Network here.
Snowpack Summary
Winds have redistributed snow in the alpine and treeline, stripping areas exposed to the wind and creating hard wind slabs in wind-loaded terrain. In total, 60-90 cm of recent snow has formed a slab that sits on a persistent weak layer of facets (sugary snow) that formed during the dry weather in early December. Though avalanche activity on this layer has slowed down in recent days, it may still be easy for humans to trigger avalanches on this layer in certain terrain features. Steep features where the underlying ground cover is smooth, places where the snowpack depths are variable, and large convex features are some of the more likely places to trigger this layer.The lower snowpack has a weak structure composed primarily of facets over a crust on the ground. It is very likely that an avalanche triggered on the persistent slab would step down to the lower facets, resulting in a full depth avalanche.
Problems
Persistent Slabs
60-90 cm of snow sits on a weak layer of facets (sugary snow). The snow below this layer consists primarily of facets all the way to the ground. Avalanches triggered on this layer will likely step down to the ground, resulting in large avalanches.
Avoid convexities or areas with a thin or variable snowpack.Be aware of the potential for full depth avalanches due to deeply buried weak layers.If triggered wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 28th, 2018 2:00PM
