Stormy weather will form fresh surface instabilities while adding a critical load to the early March layer. Choose simple terrain and tune in to signs of instability as the snowpack adjusts.
Multiple weak layers are present between roughly 100 and 180 cm deep. We expect them to be effectively bridged at low elevations, but thin-to-thick snowpack areas at treeline and above should still be treated with caution.
Expect reactive or touchy storm slabs to form as new snow continues to accumulate on the early March crust. Wind loading will accelerate slab formation in open terrain.
During the weekend storm, a widespread natural avalanche cycle occurred, size 2-3. These included storm slabs on all aspects and elevations, loose wet treeline and below, and persistent slabs on mostly on north to east aspects in the alpine and at treeline. Smaller natural and ski cut wind slabs have been the predominant activity in the days since.
Looking forward, moderate to heavy snowfall should spur the formation of a more widespread storm slab problem for Thursday.
20 to 40 cm of new snow should accumulate by end-of-day Thursday, adding to an existing 10-30 cm sitting on old wind-affected surfaces or a crust which extends up to 1900 m near Highway 1 and 2100 m in the Valhallas with moist snow immediately below.
Three formerly problematic layers of surface hoar, facets and/ or crust formed in January and February exist in the mid-snowpack, 1-2 m deep. If the recent storm cycle didn't wipe them out, we at least expect them to be effectively bridged under current conditions, especially at low elevations where the early March crust is strongest.
The remainder of the snowpack is well settled and strong.
Wednesday Night
Cloudy with increasing snowfall bringing 15 to 25 cm of new snow. 40 to 80 km/h west ridgetop wind, increasing. Treeline temperature -4 °C with freezing level rising to 1300 m.
Thursday
Mostly cloudy with easing flurries and another 5 to 10 cm of new snow. 30 to 80 km/h west ridgetop wind, easing. Treeline temperature -7 °C.
Friday
A mix of sun and cloud with scattered flurries and another 1 to 5 cm of new snow. 15 km/h west ridgetop wind. Treeline temperature -8 °C.
Saturday
A mix of sun and cloud with scattered flurries bringing 1 to 5 cm of new snow. 15 to 20 km/h northwest ridgetop wind, increasing. Treeline temperature -8 °C.
More details can be found in the Mountain Weather Forecast.
