Warm temperatures on Sunday will make higher elevations a lot more enticing than lower down, potentially drawing you into places where winds have been hard at work forming new slabs. Make observations as you travel to avoid pockets of wind loaded snow and be especially wary of shallow rocky start zones in the alpine.
Strong to extreme southwest winds have transported 20-40 cm of recent storm snow, scouring windward slopes and loading leeward features with thick wind slabs. Approach all lee and cross-loaded terrain with caution.
Keep in mind that larger wind slab releases have the potential to step down to the weak basal snowpack, resulting in very large and consequential avalanches.
Warm temperatures and rain to a possible 1500 metres will promote wet loose avalanche activity in steep terrain at lower elevations as surface layers lose cohesion.
A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure.
No new avalanches have been reported, but field information is very limited in this region.
We suspect users who head to the backcountry will see evidence of a natural wind slab avalanche cycle from recent storm snow and strong southwest winds.
20-40 cm of snow gradually accumulating over the past week is being redistributed by strong to extreme southwest winds into lee terrain in wind-exposed areas. particularly at upper elevations.
This recent snow overlies previous wind-affected snow as well as a melt-freeze crust found on sun-exposed slopes and on all aspects below 1600 m. The bond at this interface is reportedly quite strong in the adjacent west Rockies and Cariboos but remains worthy of investigation in this region where it lies more certainly within a human triggering depth.
Several more crust/facet/surface hoar layers exist in the upper and middle portions of the snowpack, however professionals in adjacent regions are beginning to de-emphasize them. The most concerning persistent weak layer by a mile is at the base of the snowpack, composed of large and weak facets formed in November. This layer is widespread and most likely triggerable in steep, rocky alpine terrain.
In general, the snowpack is weaker and shallower in this area than in areas farther west, with an average snowpack depth of around 100 cm at treeline. This makes deep persistent slab problems here quite a bit more concerning.
Saturday night
Cloudy with isolated flurries. Strong southwest winds.
Sunday
Cloudy with flurries bringing 5-10 cm of new snow. Strong to extreme southwest winds. Treeline high temperatures around 0 with freezing levels rising to 1700 metres.
Monday
Mainly cloudy with isolated flurries. Moderate to strong southwest winds easing to light west over the day. Treeline high temperatures around -6.
Tuesday
Mainly sunny. Light north winds shifting southwest. Treeline high temperatures around -8.
More details can be found in the Mountain Weather Forecast.
