Avalanche Forecast
Issued: Dec 22nd, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
A big storm recently added a significant load to a buried weak layer. Resist the urge to push into bigger terrain as human triggered avalanches remain likely. Choose conservative terrain and avoid overhead exposure to avalanche terrain.
Summary
Confidence
Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
SUNDAY NIGHT - Mainly cloudy with scattered flurries, up to 5 cm / southwest wind, 10-30 km/h / alpine low temperature near -6
MONDAY - Mainly cloudy with scattered flurries, up to 5 cm / light northwest wind / alpine high temperature near -6
TUESDAY - Mainly cloudy with isolated flurries / southeast wind, 10-25 km/h / alpine high temperature near -8
WEDNESDAY - Cloudy with sunny periods / light northwest wind / alpine high temperature near -11
Avalanche Summary
The likelihood of avalanches remains elevated, and avalanches have the potential to be very large.
On Sunday, there were preliminary reports of natural and explosives triggered avalanches up to size 3.
On Saturday, there were reports of numerous natural, human and explosives triggered avalanches up to size 3.
Numerous natural, human and explosives triggered avalanches up to size 2 were reported on Friday.
There were numerous reports on Thursday of natural, explosives and human triggered avalanches up to size 2.5. Some of these were triggered remotely.
Snowpack Summary
The South Columbias have seen 60-100 cm of new snow since Thursday night. Storm slabs are likely widespread and may be reactive to human triggering.
There is anywhere from 100-160 cm of snow on top of a widespread layer of large, feathery surface hoar crystals. This layer is suspected to have been responsible for numerous recent avalanches and it may continue to be reactive to human triggers.
A weak layer that formed in late November is now over 160 cm deep. This is the layer of concern relating to the listed persistent slab avalanche problem. The weak layer may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect.
Terrain and Travel
- Make conservative terrain choices and avoid overhead hazard.
- Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
Storm slabs are widespread and are expected to continue to be reactive.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A couple of weak layers formed in late November and early December are now over 100 cm below the surface. This layer may present as surface hoar, a crust, facets or a combination of those, depending on elevation and aspect.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 23rd, 2019 5:00PM
