Avalanche Forecast
Issued: Jan 15th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
There have been a few large persistent slab avalanches recently. These are difficult to predict, so conservative terrain selection is the best management strategy. Look for low-angle, sheltered slopes for the best snow, and the safest riding.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
FRIDAY NIGHT - Mainly cloudy / moderate west wind / alpine low temperature near -10
SATURDAY - Mainly cloudy with isolated flurries / moderate northwest wind / alpine high temperature near -8Â
SUNDAY - Mainly cloudy / moderate to strong west wind / alpine high temperature near -5Â
MONDAY - Cloudy with sunny periods / light to moderate northwest wind / alpine high temperature near -7
Avalanche Summary
On Thursday there were numerous reports of explosives triggered avalanches up to size 2.5, including one size 2.5 persistent slab avalanche.
There was a widespread natural avalanche cycle with avalanches up to size 3 reported on Tuesday night and during the day on Wednesday. There were also reports of numerous explosives triggered avalanches up to size 2.5, one of which was a persistent slab avalanche.
Over the past week, there have been several natural and persistent slab avalanches between size 2.5-3 reported in the region. These avalanches are continued reminders of the "low probability; high consequence" scenario that persistent slab problems often create.Â
Snowpack Summary
Recent fresh snow has been redistributed by moderate to strong winds and formed wind slabs in many areas. The storm earlier in the week brought rain to lower elevations, resulting in a crust that is now on the surface up to around 1800 m.
Roughly 80-120 cm of snow is now sitting on a crust that extends up to 1900 m. In isolated areas below treeline, this recent snow may be sitting on a weak layer of surface hoar.
The main feature we are monitoring in the snowpack is a layer of weak faceted snow over a hard melt-freeze crust found around 120-200 cm down. Recent sporadic, large, naturally triggered avalanches have occurred on this layer on large alpine slopes and were triggered by either smaller wind slab avalanches, or cornice falls.
Terrain and Travel
- Avoid freshly wind loaded terrain features.
- Be alert to conditions that change with elevation, aspect and exposure to wind.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Problems
Wind Slabs
Recent storm snow has been redistributed into wind slabs on leeward terrain.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
The recent storm added a big load to a deeply buried weak layer. Avalanches on this layer are becoming less likely, however, they will be large and destructive if they do happen.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 16th, 2021 4:00PM
