Avalanche Forecast
Issued: Jan 13th, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Triggering wind slab avalanches is possible in open terrain and in certain parts of the region a buried weak layer could cause large avalanches.
Summary
Confidence
Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.
Weather Forecast
MONDAY NIGHT: Clear, light wind from the west, alpine temperatures drop to -35 C.
TUESDAY: Sunny, light wind from the southwest, alpine high temperatures around -25 C.
WEDNESDAY: Mostly sunny, light wind from the southwest, alpine high temperatures around -20 C.
THURSDAY: Mix of sun and cloud, light wind from the south, alpine high temperatures around -20 C.
Avalanche Summary
Over the weekend accumulations of low density snow resulted in several small (size 1) wind slab, storm slab, and dry loose avalanches and a few larger (size 2) wind slabs.
There have also been ongoing reports of large persistent slab avalanches being reactive to human triggering over the past week. These avalanches have been reported in the Selkirks and the northern tip of the Monashees (near Blue River and Valemount). The avalanches have failed on a surface hoar layer buried roughly 100 cm below the surface, and in terrain between elevations of 1200 to 2100 m on north and east aspects. Examples include a large (size 3) avalanche that was remotely triggered on Saturday and a large (size 2.5) avalanche triggered by a snowmobile in Clemina on Friday (see photo in this MIN report). This pattern of activity suggests this problem remains a serious concern in parts of the North Columbias.
Snowpack Summary
As cold arctic air settles over the region expect wind slabs in unusual places due to recent valley winds from the north, while sheltered areas still have 20-40 cm of soft powder. A layer of surface hoar is now buried 80-120 cm below the surface and continues to be a concern in the Selkriks and the northern end of the Monashees. A facet/crust layer from late November lingers near the bottom of the snowpack and has occasionally been reactive in isolated shallow snowpack areas.
Terrain and Travel
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Don't let the desire for deep powder pull you into high consequence terrain.
Problems
Wind Slabs
Monitor changes in surface conditions as you travel through terrain. It may have blown into unstable wind slabs in open terrain or run as dry loose avalanches in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A concerning layer of surface hoar has been reactive to human triggers in the Selkirks and northern Monashees (around Blue River and Valemount). This layer is buried 80-120 cm below the surface, meaning triggering this layer would result in a large avalanche. Steep open slopes at and below treeline should be approached cautiously.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 14th, 2020 5:00PM
