Avalanche Forecast
Issued: Jan 11th, 2021 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
With new snow and extreme winds in the forecast, avalanches are expected in many areas. Choose conservative terrain and avoid avalanche terrain when there is heavy loading due to new snow or wind.
Summary
Confidence
Weather Forecast
MONDAY NIGHT - Snow, 10-20 cm / southwest wind 80-100 km/h / alpine low temperature near -4 / freezing level 1000 m
TUESDAY - Flurries, 5-10 cm / southwest wind 20-30 km/h / alpine high temperature near -3 / freezing level dropping to 500 m
WEDNESDAY - Flurries, 5-10 cm / southwest wind 20-30 km/h / alpine high temperature near -5 / freezing level 500 m
THURSDAY - Mainly cloudy / southeast wind 40-80 km/h / alpine high temperature near -3 / freezing level 700 m
Avalanche Summary
Avalanches are expected on Tuesday in many areas. Natural avalanche activity may taper off during the day, but human triggered avalanches are expected to remain likely.
At the time of publishing, there were reports of an ongoing natural avalanche cycle in the north of the region on Monday.
There were a few natural and explosives triggered storm slab avalanches size 1-2.5 reported in the region on Sunday.
A few naturally triggered wind slabs up to size 2.5 have been reported in the past few days. Additionally, there have been numerous recent reports of "whumpfing" (collapsing) on a weak layer of surface hoar down around 100 cm. See recent MIN reports HERE.
Snowpack Summary
Continued snowfall through Monday night and into Tuesday is expected to form widespread storm slabs that will likely be reactive to human triggers at all elevations.
Aside from this new snow, the main concerns vary throughout the region. In the Shames area, a weak layer of surface hoar has been reported in sheltered areas down around 90-150 cm. This layer may become active as the new snow adds load to the weak layer.
A bit further north in the Nass/Sterling/Beaupre areas, there is potentially still concern about an older weak layer overlying a crust that is now roughly 160 cm deep.
In the far north of the region, there is concern about weak snow at the bottom of the snowpack.
Big storms sometimes awaken deeply buried dormant weak layers, resulting in very large natural avalanches.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid freshly wind loaded terrain features.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Storm Slabs
New snow and extreme southwest winds on Monday night will form widespread storm slabs that will likely remain reactive on Tuesday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
New snow and extreme winds may overload deeply buried weak layers, resulting in very large avalanches. Choosing conservative terrain away from overhead hazard is the best way to manage this problem.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 12th, 2021 4:00PM
