The track and intensity of the incoming weather system are uncertain.
Hot spots up to 30 cm possible.
Where wind driven snow exceeds 20 cm, the avalanche danger is CONSIDERABLE.
New snow coupled with moderate southwest wind will likely develop fresh wind slabs in lee terrain features. They may be particularly reactive at upper treeline where they have formed over a crust.
Persistent weak layers of crust, facets, or surface hoar are buried up to 250 cm deep. Triggering is most likely on northerly aspects, or later in the day on sun-exposed slopes when the upper snowpack has been weakened.
While details are lacking, a large (~size 3) persistent slab avalanche was remotely triggered on a north-facing alpine slope on Friday. I appeared to occur on a steep, rocky slope with a thin-to-thick snowpack.
Wet loose avalanches continue to be reported daily with the recent warm temperatures and strong sun. With cooler, cloudy conditions this trend is expected to taper.
Up to 20 cm is possible by end of day Monday. This new snow will bury crusty surfaces across most terrain, except in high alpine north-facing areas, where dry, wintry snow can still be found, and isolated wind slabs may linger. On solar aspects and lower elevations, surface crusts are less robust and possibly breakable and/or moist snow.
Several persistent weak layers are buried up to 250 cm deep. While triggering these layers is becoming unlikely, they present a low-probability, high-consequence problem. A cornice fall (large load) may be enough to trigger this slab.
Sunday Night
Mostly cloudy. 2 to 5 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1000 m.
Monday
Cloudy. 5 to 10 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -4 °C.
Tuesday
Mostly cloudy. 10 to 15 cm of snow. 30 km/h south ridgetop wind. Treeline temperature -4 °C.
Wednesday
Mix of sun and clouds. 1 to 5 cm of snow. 20 km/h south ridgetop wind. Treeline temperature -4 °C.
More details can be found in the Mountain Weather Forecast.
