Avalanche Forecast
Issued: Jan 21st, 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.
astclair,
Avalanche Canada
Triggering avalanches may be possible in specific areas with stiff, wind-drifted snow or with a buried weak layer. Monitor for these conditions where you travel on Friday.
Summary
Confidence
Weather Forecast
Thursday night: Mostly clear, light northwest winds, alpine temperatures dropping to -20 C.
Friday: Mainly sunny, light northwest winds, alpine high temperatures around -15 C.
Saturday: Increasing cloud, light southwest winds, alpine high temperatures around -16 C.
Sunday: Cloudy, isolated flurries with a trace of snow possible, light south winds, alpine high temperatures around -12 C.
Avalanche Summary
Recent strong southwest winds have formed wind slabs in lee features at upper elevations that may be possible to human trigger. On Sunday, observers reported human-triggered avalanches in wind-stiffened snow in the south of the region (check out the MIN reports here and here). Cornices may be reaching their breaking point and can act as triggers on slopes below.
On Saturday, professional operators reported a small (size 1) avalanche releasing 40 cm deep on the Jan 11th surface hoar layer. Observers south of Valemount also reported reactivity on the surface hoar buried down 45 cm. They saw shooting cracks and slab activity at 1700m on an easterly aspect.
Since field observations in this region are limited, please consider submitting your observations to the Mountain Information Network.
Snowpack Summary
Recent winds have scoured snow surfaces, loaded cornices, and formed stiff wind slabs in alpine and upper treeline areas.
A weak of layer of surface hoar can be found buried 40-60 cm deep. This layer demonstrated reactivity over the weekend from observers in the south of the region near Valemount. It is most suspect in sheltered, open slopes at and below treeline. Although results from recent snowpack tests show increasingly resistant results (check out this MIN from near Barkerville), careful assessment is warranted. Below 1600 m, 20-30 cm of snow is settling above a decomposing melt freeze crust.
Deeper in the snowpack, a couple of older persistent weak layers may still be identifiable from late and early December, consisting of surface hoar and a crust with faceted snow and buried anywhere from 70-150 cm deep. Prolonged periods of inactivity and unreactive snowpack test results suggest that these layers have trended towards dormancy.
Terrain and Travel
- Carefully evaluate steep lines for wind slabs.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
- Avoid exposure to slopes that have cornices overhead.
Problems
Wind Slabs
Strong winds have redistributed recent snow into hard wind slabs on lee features at upper elevations that may be possible trigger. Cornices are adjusting to a rapid load and may trigger avalanches on the slopes below.
Aspects: North, North East, East, South East, South, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar buried Jan 11 may be found 40-60 cm deep on open, sheltered slopes near and below treeline. There is uncertainty in the distribution and sensitivity of this persistent slab problem across the region.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 22nd, 2021 4:00PM
