Avalanche Forecast
Issued: Dec 20th, 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.
jleblanc,
Avalanche Canada
Strong wind will increase all day Tuesday. Watch for changing conditions as wind slabs will become more reactive.
Summary
Confidence
Weather Forecast
An Arctic ridge of high pressure will continue to build from the Yukon into the B.C interior bringing clear skies and cold conditions across the province with outflow winds through Tuesday morning. Abundant moisture from the Pacific will invade the province starting on Tuesday night.
MONDAY NIGHT: Clear skies / Strong to extreme northwest wind / Low of -16 at 2000 m.
TUESDAY: Increasing cloudiness / Flurries 3-5 cm / Strong west wind / High of -12 at 2000 m.
WEDNESDAY: Snow 20-30 cm / Strong to extreme southwest wind/ High of -7 at 2000 m.
THURSDAY: Flurries / Moderate southwest wind / High of -14 at 2000 m.
Avalanche Summary
Numerous loose dry and storm slabs avalanches (size 1-2) have released naturally at all elevations on steep terrain features after the last storm.
If you go out in the mountains, please consider filling out a Mountain Information Network report.
Snowpack Summary
20-40 cm of recent new snow has been redistributed by Southwest winds during the last storm, creating wind slabs on North and East facing features. As the wind shifts to the Northwest, expect to see fresh wind slabs developing on slopes that have not seen them yet.
The concerning layer within the snowpack is the early December facet/crust combo which is now buried between 60-100 cm down. This layer generally exists below 1800 m and is most concerning in the area west of Blue River. In some places, the crust starts to decompose and show sporadic test results.
Terrain and Travel
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
Problems
Wind Slabs
Strong shifting winds will likely redistribute the recent storm snow and create reactive wind slabs on all open terrain. Expect cross-loading to develop throughout the day Tuesday. Human-triggered wind slabs are most likely during their formation.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of facets can be found above a crust from early December, which is now down 80 to 150 cm and most concerning in the terrain West of Blue River at the treeline elevation. Although this persistent weak layer showed sporadic and various test results, keep in mind that it's a low probability / high consequence scenario, if triggered.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Dec 21st, 2021 4:00PM
