Update 6:45 am: Limit your exposure to avalanche terrain. Snowfall will form surface instabilities while testing deeper layers that have already produced many destructive avalanches.
Forecast snowfall continues to load multiple weak layers present roughly 80 to 180 cm deep. Large, destructive avalanches are expected to continue failing on these layers.
Expect reactive or touchy storm slabs to form on the surface, but storm failures may occur as deep as the early March crust, already at a critical load in many areas. Wind loading will accelerate slab formation in open terrain.
During the storm on the weekend, a widespread natural avalanche cycle occurred. These included storm slabs size 2-3 and persistent slabs size 3-3.5.
On Monday, many persistent slabs size 3-3.5 were triggered in explosive control work throughout the region. This scary MIN report from the Esplanades describes very large persistent slab avalanches remotely triggered by riders from hundreds of meters away.
Expect similar activity to resume with forecast weather.
25 to 40 cm of new snow should accumulate by end-of day Thursday, adding to 20 to 50 cm already overlying firm early March surfaces, including a crust which extends up to 1800 m in the north and 2200 m in the south. We're now at the point where avalanches failing at this interface will be large and destructive.
Three more layers in the mid-snowpack remain suspect.
One or two surface hoar layers buried in February are found 60 to 120 cm deep. In some areas these sit on a thin crust.
A deeper, widespread layer buried in late January, made up of surface hoar, facets, and/or a crust, sits 100 to 180 cm deep. Surface hoar within this layer is most preserved and largest in sheltered terrain at treeline and below.
Wednesday Night
Cloudy with increasing snowfall bringing 20 to 30 cm of new snow. 30 to 60 km/h southwest ridgetop wind, increasing. Treeline temperature -8 °C.
Thursday
Mostly cloudy with lighter flurries bringing another 5 to 10 cm of new snow. 30 to 50 km/h west ridgetop wind, easing. Treeline temperature -10 °C.
Friday
A mix of sun and cloud with easing scattered flurries and another 5 to 10 cm of new snow, including overnight. 20 km/h west ridgetop wind. Treeline temperature -10 °C.
Saturday
A mix of sun and cloud with scattered flurries bringing less than 5 cm of new snow. 20 km/h northwest ridgetop wind. Treeline temperature -10 °C.
More details can be found in the Mountain Weather Forecast.
