Overnight flurries and steady south winds will continue to add to the storm slab problem. Stick to conservative terrain and give the new snow time to settle and bond.
A number of buried weak layers remain possible to trigger. These layers appear to be most problematic in upper treeline and alpine elevations, in shallow, variable, rocky start zones. A sensitive wind or storm slab overlying this problem could serve as the perfect trigger for a destructive step-down avalanche.
Overnight flurries and steady south winds will continue to add to surface instabilities Friday. Watch for lingering storm slabs and freshly formed wind slabs, the most reactive deposits will be in areas influenced by the wind.
On Thursday, our field team observed 2 recent natural avalanches. With reduced visibility, the size 2 avalanches were 60-80 cm deep and suspected to have failed on a rain crust. A powder cloud was observed on Hudson Bay Mountain on Thursday morning as a natural avalanche occurred in one of the gullies.
On Wednesday, skiers triggered a large, size 2 avalanche near Ningunsaw. The Deep Persistent avalanche was triggered on an east aspect near ridgetop in a thin, rocky start zone and failed on basal facets.
Reports Tuesday documented a very large (size 3.5) natural deep persistent slab avalanche observed in the Babines on a northwest aspect around 1700 m and failing on basal facets 150 cm deep. This speaks to the importance of conservative terrain selection through this period of active weather. Several less surprising small to large (size 1-2.5) naturals were also observed in steep leeward terrain in the same area.
Observations from Monday in the snowier southwestern part of the region show our recent storm snow reacting to ski cutting, which produced numerous small (up to size 1.5) storm slabs on steep slopes at treeline and below with crowns up to 40 cm. Isolated natural releases were also observed in the alpine.
If you are out in the backcountry, please share your observations with the Mountain Information Network!
15-30 cm snow accumulated in the region by end of Thursday, and strong south winds quickly promoted new slab formation over the day. Fresh snow adds to 50-80 cm of recent storm snow that has been getting continuously blown into wind slabs by southwest winds at treeline and above. The growing storm total sits on a crust from the warming event on January 25th and the bond at this interface is still in question, especially with forecast loading from new snow and wind.
The mid and lower snowpack continues to bond and stabilize. A few concerning weak layers can still be found in the top meter of the snowpack including a surface hoar layer from early January and a crust from late December.
Thursday night
Flurries, 5-10 cm tapering overnight. South winds easing to 30 km/hr. Treeline low temperature -9 C with freezing level dropping to valley bottom.
Friday
Mostly cloudy with isolated flurries, 5 cm. Storm totals 15-30 cm. Southwest winds 20-30 km/hr. Treeline high temperature -5 C.
SaturdayIsolated flurries, up to 5 cm. Southwest wind gusting to 50 km/hr with approaching storm. Treeline high temperature -2 C.
SundaySnow, 10-20 cm. Southwest winds gusting over 60 km/hr. Treeline high temperature -2 C.
More details can be found in the Mountain Weather Forecast.
