Start on small slopes and be ready to retreat to mellow terrain if you start seeing signs of instability.
Avalanche danger should start to decrease after the snow and wind taper off.
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.
A winter-like storm has increased the likelihood of avalanches at all elevations. This storm snow may be particularly reactive at upper treeline where it's sitting on a crust, and on north and east aspects that are wind-loaded.
While details are lacking, a size 3 persistent slab avalanche with a wide propagation was remotely triggered on a north-facing alpine slope on Friday. It appeared to occur on a steep, rocky slope with a thin-to-thick snowpack.
On Monday and Tuesday, a variety of small to large (size 1-2) natural and explosive triggered avalanches were reported around the region. Wind and Storm slabs in the alpine and treeline, and wet loose at treeline and below.
Expect 30-55 cm of storm snow to have accumulated by Wednesday morning. This covers crusty surfaces across most terrain, except in high alpine north-facing areas, where dry, wintry snow can still be found.
Periods of strong wind around Stewart and to the north may be redistributing that recent snow onto leeward slopes.
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.
Tuesday Night
Mostly cloudy. 2 to 5 cm of snow, possible hotspots of 10 cm or more. 30-50 km/h northeast ridgetop wind around Stewart and to the North. 15 km/h northeast ridgetop wind south of Stewart. Treeline temperature -5 °C.
Wednesday
Mostly sunny. 1 to 3 cm of snow. 10-30 km/h northwest ridgetop wind. Treeline high -1 °C.
Thursday
Mix of sun and clouds. 1 to 2 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -3 °C.
Friday
Mix of sun and clouds. 1 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -3 °C.
More details can be found in the Mountain Weather Forecast.
