Avalanche Forecast
Issued: Jan 27th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
JH,
Avalanche Canada
Fresh windslabs should stabilize quickly as temps cool, but may remain triggerable on Saturday.
The surface hoar layers from early January will linger for a little longer unfortunately. Skier traffic may have reduced the chances of triggering this weakness on our more popular runs, but approach terrain that is off the beaten path with extra caution.
Oh yeah...it's real cold again too, bring extra layers and leave yourself a little extra buffer to get out safely at the end of the day.
Summary
Confidence
High
Avalanche Summary
Artillery control on Friday produced numerous size 2-2.5, and a few size 3, slab avalanches in the Alpine and at Treeline. These are suspected to have been primarily windslabs, with some propagating more widely, suggesting failure on the early January surface hoar. These avalanches started as fast moving powder clouds, but quickly ground to a halt when they hit the refrozen snow mid-track (~1700m).
On Wednesday, a Skier triggered an avalanche on McGill shoulder,the failure plane for this was suspected to be an early January surface hoar layer down 50cm. Parks Canada staff also triggered soft slabs, up to size 1, down 30-40cm on a sun crust on steep solar aspects at treeline.
Snowpack Summary
Wind slabs formed recently in the alpine and at treeline with strong SW winds. Warm temps this week have left a surface crust below ~1700m, and a buried sun/temperature crust (Jan 21st) on steep south facing terrain, down 30-40cm around treeline.
The early January Surface Hoar layers (Jan 3rd and 12th), are buried down 40-70cm, and most likely to be rider triggered at treeline.
The mid-pack facets are slowly rounding and gaining strength, while large facetted crystals and the Nov 17 facet/SH/crust weakness can still be found near the base of the snowpack in many areas.
Weather Summary
An arctic ridge of high pressure will bring clear skies, cold temps and light outflow winds to our area through the weekend.
Tonight: Cloudy periods with isolated flurries. Alpine Low -22*C, Light NE ridgetop winds.
Saturday: Sunny. Alpine High -21*C. Light NE wind.
Sunday: Mostly Sunny. Low -22*C, High -19*C. Light NW winds.
Monday: Cloudy periods, isolated flurries. Low -19*C, High - 16*C. Light W wind.
Terrain and Travel Advice
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Southwest winds have built wind slabs at ridge-lines, lee areas, and cross loaded features. If triggered, wind slabs may step down to the persistent surface hoar layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
This layer has been most reactive around treeline, in areas that have not seen significant skier traffic since early January.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 28th, 2023 4:00PM
