Be ready to manage new storm / wind slabs, but don't let them overshadow the destructive persistent slab lurking below. Let the high consequence of triggering one guide your terrain choices.
A crust / facet layer from mid-November is buried 50 to 100 cm deep. Continued loading and copious water in the snowpack keeps the chances of triggering it elevated. Many recent destructive avalanches are associated with this problem.
10 - 25 cm of new snow will build new storm slabs (wind slabs where accumulations are less) on Wednesday. Expect the greatest danger in the alpine.
Observations from the Duffey on Monday included five natural releases in the size 2.5 to 3 range, in addition to explosives results. As suspected with the size 3's in the Hurley and Upper Lillooet on Sunday, all are reported to have failed on the mid-November crust.
Looking forward, moderate snowfall and warming Tuesday night should promote similar activity. Although a shift toward new snow problems is expected, it's certainly not time to dismiss the persistent problem.
10 - 25 cm of new snow should accumulate at higher elevations by Wednesday morning (expect rain below about 1500 m), covering a rain-soaked snowpack to about 2100 m and adding to somewhat uncertain dry snow accumulations above this elevation.
A crust with facets, formed in mid-November, was buried 50 to 100 cm before the storm. Recent very large wet slab and persistent slab releases failed on this layer and continuing loading prevents us from gaining confidence in it, even as temperatures cool.
Tuesday Night
Cloudy with continuing precipitation bringing 10 to 25 cm of new snow above 1700 m, rain as high as 1500 m. 30 km/h southwest ridgetop wind. Treeline temperature reaching 0 °C with a period of 1700 m freezing levels.
Wednesday
Mostly cloudy with isolated flurries. 30 km/h southwest ridgetop wind. Treeline temperature -5 °C. Freezing level 1100 m.
Thursday
Mostly cloudy with continuing flurries bringing 10 to 20 cm of new snow, including overnight amounts. 15 to 30 km/h south ridgetop wind, easing. Treeline temperature -3 °C. Freezing level to 1400 m.
Friday
Mix of sun and clouds wit up to 5 cm of new snow from overnight. 10 km/h southwest ridgetop wind, easing. Treeline temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
