High consequence persistent and deep persistent slab avalanches have been reported every day over the past week. Stick to low angle terrain away from any overhead hazard.
Read more in our latest forecaster blog.
Expect transport and fresh slabs where wind impacts loose snow. Northeast arctic outflow winds may reverse-load features and build slabs in less common areas.
A reactive surface hoar layer is found 40-70 cm deep throughout the region. Be especially cautious around steep openings treeline and below.
A layer of large and weak facets sits near the base of the snowpack. This layer has most recently been reactive in upper treeline/lower alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow previously undisturbed terrain or by first triggering a layer further up in the snowpack.
On Thursday a few very large (size 2.5-3) natural wind slab avalanches were reported around 1800-2000 m. Additional ongoing evidence of weak basal facets continued with a size 3 deep persistent avalanche reported on a steep southeast slope at 2400 m.
Both natural and human-triggered persistent and deep persistent slab avalanches continue to be reported daily. Last Wednesday there was a report of a remotely triggered (from a distance) size 2 persistent slab avalanche at treeline on a south aspect. There was also a size 3 naturally triggered deep persistent slab avalanche with a wide propagation reported on a south aspect in the alpine.
On Monday, a fatal skier-triggered avalanche incident occurred in the Selkirks near Revelstoke. The avalanche was on an east aspect at 1900 m. It occurred on a steep, unsupported open slope below treeline and failed on a weak layer of surface hoar buried in early January. This large avalanche (size 2) had a crown depth of 50 cm.
Last weekend (Saturday), a fatal avalanche Incident occurred in the Oasis riding area south of Valemont. This avalanche resulted in a rider fatality. This was a remotely triggered (from a distance) size 2.5 deep persistent slab avalanche on a north-northwest aspect at 2100 m. More details can be found here.
Avalanches like these are most likely to be triggered on steep, shallow and previously undisturbed slopes. Your best defence at this time is to stay diligent in choosing low-consequence terrain that has been heavily trafficked throughout the winter. Stay disciplined and adjust your expectation for this winter.
Surface snow varies by elevation, with recent warm temperatures turning snow moist around treeline elevations and now heading into a cooling trend. West and north winds will continue to affect exposed terrain and form wind slabs near ridgetops. 20-60 cm of recent snowfall sits above a layer of surface hoar as well as a sun crust on steep solar aspects.
A prominent layer of buried surface hoar can be found roughly 50-90 cm deep. It is found in some places but not in others, and has been recently reactive to human triggering. The bottom of the snowpack is made up of large weak facets buried in late November, causing the Deep Persistent Slab problem for this region.
Friday night
Isolated flurries, 5 cm. Ridge wind northeast 15-30 km/hr. Alpine temperature -16 C. Artic air bringing cold temperatures and northerly outflow winds.
Saturday
Increasingly Sunny. Ridge wind northeast 15-30 km/hr. Alpine temperature -20 C.
SundaySunny. Ridge wind northeast 20-30 km/hr. Alpine temperature -23 C.
MondaySunny. Ridge wind northeast 5-15 km/hr. Alpine temperature -25 C.
More details can be found in the Mountain Weather Forecast.
