Reactive storm slabs are widespread at all elevations. Evaluate terrain features carefully. Avoid large unsupported slopes and navigate wind loaded features cautiously.
Weak faceted grains above the early December crust found around 80 to 150 cm deep is most concerning in areas where the snowpack thins at treeline elevations.
Avoid likely trigger spots such as steep, rocky start zones. Smaller avalanches have the potential to step down to deeper weak layers. Read more about it here.
Strong south/southwest winds will create deeper deposits in wind loaded features.
Larger avalanches could be triggered in sheltered treeline terrain features where slabs are forming over surface hoar.
MONDAY NIGHT: Up to 10cm of snow overnight. Winds drop to moderate southwesterlies.
TUESDAY: Chance of flurries with light southeast winds. Alpine high of -15.
WEDNESDAY: Clearing skies, isolated flurries. Light southwest winds. Alpine high of -15.
THURSDAY: Light snowfall begins early morning with increasing southerly winds. Temperatures begin to rise with an alpine high of -10.
On Sunday, several natural and skier triggered slabs were observed in wind loaded features at treeline and above to size 2.
Cornice falls have triggered numerous slabs this week, as they land on the slope below. Navigate around cornices carefully, both on ridgelines and on the slopes below them with care - they are able to effect deeply buried weak layers.
Several large and destructive persistent slab avalanches have been naturally and skier triggered in the over the last week up to size 3, failing on the early December crust/facet interface. Each had wide propagation and ran several hundred metres. The avalanches were all triggered in a rocky and thin area.
Up to 40 cm of low density storm snow has fallen this week and has been redistributed into wind loaded features at treeline and above by strong southwest winds.
A layer of weak surface hoar crystals can be found 30-50cm deep in sheltered terrain features at alpine and treeline elevations, and in open features like cut blocks below treeline.
The crust formed by the early December rain event sits 100-150cm deep and is found up to 2200 m. Faceted grains sit above, creating a weak interface that is still reactive to human triggers. This layer is most reactive at treeline in areas where the snowpack thins and the weak interface is much closer to the surface. This layer has the potential to produce large and destructive avalanches if triggered. Natural and skier triggered avalanches have occurred in this layer to size 3 in the last week.
