Avalanche Forecast

Moderate - The snowpack structure is generally well understood.

FRIDAY NIGHT: Increasing clouds and flurries. Variable winds, 10-20 km/hr. Alpine low temperature -9 C. Freezing level dropping to valley bottom.

SATURDAY: Snow begins in the early morning, up to 15 cm accumulation through the day. Increasingly strong and gusty west wind, 30-45 km/hr. Alpine high temperature -4 C. Freezing level below 1000 m. 

SUNDAY: Clear and sunny. Northwest-west wind, 15-30 km/hr. Alpine high temperature -9 C. Freezing level valley bottom. 

MONDAY: Mostly cloudy with flurries, trace to 5 cm accumulation. Southwest wind 10-20 km/hr. Alpine high temperature -9 C. Freezing level valley bottom. 

Note that there are very few field observations from the Kootenay Boundary this early in the season. Backcountry users need to be skilled in assessing conditions and decision making. If you venture out in the mountains, please share your observations and photos on the Mountain Information Network.

On Wednesday, Dec 1 natural wet avalanches to size 2 failing in steep treeline features were reported from the Highway 3 corridor near Stagleap Provincial Park. The Okanagan edge of the Kootenay Boundary also reported evidence of a natural storm cycle up to size 2. 

Explosive control work on Tuesday, Nov 30th produced several size 2 wind slabs on eastern aspects in alpine features, failing on a melt freeze crust. 

Over the previous week several size 1.5 - 2 storm slabs have been triggered near Nelson, and a natural avalanche cycle size 1-2 was observed from north facing alpine start zones.

The snowpack is drying and cooling with dropping temperatures. Mixed precipitation and rain have left a melt freeze crust at the surface, overlying a moist to wet upper snowpack with multiple crusts throughout. Isolated areas of sheltered alpine features may still hold dry wind effected snow. 

The mid-November crust is down 40-90cm and is up to 10cm thick. At higher elevations the lower snowpack is a series of crust and facet layers with up to 20 cm of faceted snow sits on the ground. The entire snowpack was saturated at mid and lower elevations and is now refrozen.

Snowpack depths at treeline range from 50-100 cm, with alpine depths exceeding 120 cm in areas. Below 1700m, snowpack depths decrease rapidly with poor coverage in many below treeline areas.

• Be alert to conditions that change with elevation and wind exposure.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.