Avalanche Forecast
Issued: Jan 23rd, 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.
dsaly,
Avalanche Canada
Avalanche hazard is improving, stick to good travel habits. Be wary of lurking wind slabs and large cornices.
Summary
Confidence
Weather Forecast
Saturday night: Increasing cloud / light southwest winds / alpine low temperature -18
Sunday: Mostly cloudy, isolated flurries / light southeast winds / alpine high temperature -10
Monday: Cloudy / light south winds / alpine high temperature -12
Tuesday: Cloudy with isolated flurries / light southeast winds / alpine high temperature -11
Avalanche Summary
Outside of a handful of small size 1 wind slabs, a few cornice failures, and loose dry sluffing in steep and southerly terrain, there have been no recent notable avalanche reports in the region.
With the strong winds last Tuesday, operators in the region reported small to large (size 1-2) wind slabs releasing naturally as well as several size 1-2 explosive-triggered cornices.
Last Monday and Tuesday, several operators in the region reported small (size 1-1.5) human-triggered avalanches releasing on a weak layer of surface hoar on north, east and southeast aspects at treeline and below treeline elevations. These avalanches were breaking 25-45 cm deep.
Snowpack Summary
Previous winds scoured snow surfaces, loaded cornices, and formed stiff wind slabs in the alpine and around treeline. A thin sun crust may be found on steep solar aspects. Clear skies and cold temperatures are encouraging surface hoar growth and surface faceting. Below 1700-1800 m, 20-30 cm of snow is settling above a decomposing melt freeze crust.
Observers continue to find a preserved layer of surface hoar down 50-70 cm in sheltered, open slopes at and below treeline. Recent snowpack tests have produced sudden results on this layer, other tests have found it unreactive, as such it continues to warrant slope-specific assessment.
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 100-200 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.
- Large cornice falls are dangerous on their own.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Wind slabs are stubborn, but if triggered will be heavy and dense. Use caution around cornices.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar buried Jan 11 may be possible to trigger on open, sheltered slopes near and below treeline (above 1700 m). This weak layer can be found buried 50-70 cm deep. Recent avalanche activity demonstrates that this layer is likely to be reactive where it has been preserved. Recent activity has been specific to the southern half of the region.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Jan 24th, 2021 4:00PM
