Avalanche Forecast
Issued: Jan 24th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
dsaly,
Avalanche Canada
Remain cautious of wind slabs in steep and immediate lee features. Be wary of large cornices.
Summary
Confidence
Weather Forecast
Sunday night: Mostly cloudy, isolated flurries / light southeast winds / alpine low temperature -18
Monday: Cloudy with isolated flurries / light south winds / alpine high temperature -10
Tuesday: Cloudy with sunny breaks / light southeast winds / alpine high temperature -10
Wednesday: Cloudy with sunny breaks / light east winds / alpine high temperature -12
Avalanche Summary
Over the last few days, reports have documented a handful of small size 1-1.5 wind slabs, a few large cornice failures, and loose dry sluffing in steep and southerly terrain.
Last Wednesday, operators in neighboring Glacier National Park reported several large (size 2-2.5) wind slabs releasing naturally on a variety of aspects (north, east, and south). Two natural cornice failures were reported in Glacier National Park on Wednesday releasing above north-facing slopes.
This MIN from Clemina Creek last weekend reports that the Jan 11th surface hoar was cracking and propagating in sheltered treeline and below treeline areas where it was buried 40-50 cm deep. Now trending unreactive, this is a layer we will continue to monitor.
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 1600 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 40-70 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
Persistent Slabs
A weak layer of surface hoar buried Jan 11 may be found 40-70 cm deep on open, sheltered slopes near and below treeline. Although likely unreactive to skiers, there is uncertainty as to the distribution and reactivity of this persistent slab problem across the region.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 25th, 2021 4:00PM
