Avalanche Forecast
Regions: Banff Yoho Kootenay.
A storm starting Thursday will likely increase the avalanche danger over the next few days.
Weather Forecast
A storm system is on the way starting Thursday. Expect increasing winds over the day in the alpine from the W/SW, and 5-10cm by the end of the day. -20C in the AM and warming slightly to -15C in the afternoon at treeline. Another 10cm, moderate to strong West winds and temperatures between -5C and -10C expected on Friday.
Snowpack Summary
15-30 cm storm snow in the last few days. Previous wind slabs have been observed sitting over facets in lee areas of the alpine and some treeline locations. 50-70 cm over the Dec 2 crust/facet combo which exists below 2200 m. Shallow snowpack areas (<100cm) have weaker basal facets. Snowpack depths at treeline are from 120-160 cm.
Avalanche Summary
There was a small wind slab triggered on Ochre Spring creek yesterday at treeline. This slab was overlying facets from last weeks cold snap. No other avalanches reported or observed.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Thursday
Avalanche Problems
Wind Slabs
Recent wind slabs overly facets from last weeks cold spell. Increasing winds Friday and snow inputs over the next couple of days will likely add to the reactivity of this problem.
- Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
The Dec. 2 crust/facets are down 50-80 cm and have not yet been a widespread problem. Uncertainty remains about what it will take to activate this layer which seems most pronounced in Kootenay.
- Be cautious with steep or unsupported slopes.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 2.5