Purcells

The incoming storm is driving the avalanche danger.

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The new snow will be very reactive this weekend. Expect storm slabs anywhere deeper deposits have formed and fast-moving dry loose avalanches in steep terrain. Natural avalanches are possible on wind-loaded slopes.

Flurries on Saturday will bring storm totals to 10 to 25 cm, with deeper deposits in wind-loaded areas. The new snow will likely bond poorly to old surfaces, which include melt-freeze crusts on sun-exposed slopes, surface hoar or facets on shaded slopes, and wind-affected snow at higher elevations. Some areas also have slightly deeper surface hoar layers that have not yet been loaded by a slab (20 to 30 cm deep).

A weak layer of facets from early December is buried 50 to 100 cm deep, or as shallow as 30 cm near Invermere. While recently inactive, this layer could reawaken with heavy loading or warming.

The base of the snowpack consists of a thick crust with facets or depth hoar in many areas.

Friday Night

Cloudy with 5 to 10 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -6 °C.

Saturday

Mostly cloudy with 0 to 5 cm of snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -10 °C.

Sunday

Mix of sun and cloud with 0 to 3 cm of snow. 10 km/h south ridgetop wind. Treeline temperature -10 °C.

Monday

Mix of sun and cloud with 0 to 2 cm of snow. 10 km/h southeast ridgetop wind. Treeline temperature -15 °C.

More details can be found in the Mountain Weather Forecast.

• Use conservative route selection. Choose simple, low angle terrain with no overhead hazard.
• Avoid freshly wind-loaded terrain features.
• Be aware of the potential for remote triggering and large avalanches due to buried surface hoar.
• Dial back your terrain choices if you are seeing more than 20 cm of new snow.