Avalanche Forecast
Issued: Dec 16th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
dsaly,
Avalanche Canada
New snow on a buried weak layer will become increasingly reactive to human triggers, especially where impacted by wind.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
WEDNESDAY NIGHT - Mainly cloudy with isolated flurries, up to 10 cm / southwest wind, 20-50 km/h / alpine high temperature near -7Â
THURSDAY - Mainly cloudy with flurries, 5 cm / southwest wind, 25-45 km/h / alpine high temperature near -8Â
FRIDAY - Mainly cloudy with flurries, 5-15 cm / southwest wind, 45-65 km/h / alpine high temperature near -5
SATURDAY - Mainly cloudy with flurries, 10-20 cm / southwest wind, 45-70 km/h / alpine high temperature near 0
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 accumlate.
Several large natural avalanches were reported last Friday 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 10-30 cm of new snow has accumlated around the Cariboos, with a few exceptions receiving up to 40 cm (mostly around Blue River). This low density snow has buried a layer of surface hoar in many areas. Expect to find more reactive slabs as new snow accumlates and gains cohesion.
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
10-20 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 17th, 2020 4:00PM
