Stick to simple terrain free of overhead hazard as storm slabs build and temperatures rise. A weak snowpack sits below.
Expect increased reactivity on wind affected features. Storm slabs may involve moist/wet snow with possible rain, and rising freezing levels.
Highest accumulation
On Monday storm snow was reactive to explosive and human triggers, producing size 1-2 avalanches.
We expect reactivity to continue, as storm slabs continue to build with possible natural activity in areas with heavy loading of snow, wind or rain. If you are out and about in the mountains, please consider posting your observations to the MIN.
By Wednesday afternoon up to 25 cm of new snow is expected over the recent rain crust which sits over 30-50 cm of recent snow. Higher elevations are likely wind-affected with deep deposits on north and east facing ridgelines. Lower elevation snow will likely be moist from rain or mixed precipitation.
A layer of faceted snow or surface hoar, and a crust from mid November is buried 30-70 cm deep. Several crusts exist lower in the snowpack and weak, sugary facets can be found near the ground.
Snowpack depths range from 70–120 cm, thinning quickly at lower elevations. In many areas, especially below treeline, slopes lack enough snow to cover ground roughness and produce avalanches.
Tuesday Night
Partly cloudy. 2 to 5 cm of snow. 40 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 1000 m.
Wednesday
Cloudy. 10 to 25 mm of precipitation as snow or rain at treeline. Highest amounts are expected in the West Purcells and Bull region. 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level rises from 1300-2000 m over the day.
Thursday
Mostly cloudy. 10 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1300 m.
Friday
Mostly cloudy. 1 to 5 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 200 m.
More details can be found in the Mountain Weather Forecast.
