Avalanche Forecast
Issued: Dec 15th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
kdevine,
Avalanche Canada
New snow on a buried weak layer may be reactive to human triggers, especially in wind loaded features. Areas near Blue River that received more than 25 cm of new snow since Monday afternoon are likely CONSIDERABLE at treeline.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations. Recent weather patterns have resulted in a high degree of snowpack variability within the region.
Weather Forecast
TUESDAY NIGHT - Cloudy with scattered flurries, 2-10 cm / southwest wind, 30-50 km/h / alpine low temperature near -9Â
WEDNESDAY - Mainly cloudy with isolated flurries / southwest wind, 20-40 km/h / alpine high temperature near -7Â
THURSDAY - Mainly cloudy with flurries, 5 cm / southwest wind, 20-40 km/h / alpine high temperature near -8Â
FRIDAY - Mainly cloudy with flurries, 5-10 cm / southwest wind, 20-40 km/h / alpine high temperature near -7
Avalanche Summary
New snow and moderate to strong southwest winds have likely formed slabs that will probably be reactive to human triggers, especially in wind loaded areas, and in places that have seen more than 20 cm of new snow since Monday.
Several large natural avalanches were recently reported at Chappel Creek (see this MIN report). These avalanches occurred on south aspects at treeline elevations. Based on the depth of these avalanches, they likely failed on recently buried surface hoar and/or sun crust layers.Â
Snowpack Summary
About 5-15 cm of new snow has fallen in the Cariboos since Monday evening, with a few exceptions receiving up to 40 cm (mostly around Blue River). This new snow has buried a layer of surface hoar in many areas. The new snow combined with moderate to strong southwest winds may be forming slabs in open areas, which will be most reactive in the areas that received the most new snow.
A weak layer that was buried about a week ago is now down 30-60 cm. In many areas the weak layer exists as a crust, and in some areas, it has been found as surface hoar. There is uncertainty as to how well the new snow may be bonding to this layer.
Near the base of the snowpack is a crust that was buried in early November. This crust likely has weak facets associated with it. There have been no recent avalanches reported on this layer, though it may be possible to trigger from shallow, rocky terrain.
Terrain and Travel
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Avoid freshly wind loaded terrain features.
- Investigate the bond of the recent snow before committing to your line.
Problems
Persistent Slabs
10-15 cm of new snow sits on a weak layer of surface hoar. Expect this layer to be most reactive in wind loaded terrain.
Some areas near Blue River likely have up to 40 cm of new snow on this layer, and it will be most reactive in places like this.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 16th, 2020 4:00PM
