Avalanche Forecast
Regions: Blue River, Clearwater, Clemina, North Monashee, Premier.
Keep selecting conservative terrain as new snow stabilizes and watch for signs of instability like shooting cracks or recent avalanches. Shallow, rocky areas remain especially suspect.
Confidence
Moderate
Avalanche Summary
Tuesday was likely a busy day for natural and human-triggerable avalanches as moderate to heavy snowfall and elevated winds affected the region.
A size 2 (large) deep persistent slab was triggered from a 20 m distance in the Clemina alpine on Sunday on a NE aspect. It was 70 cm deep, failing at the base of the snowpack. This highlights the problematic basal snowpack structure in the region.
Aspects lee of northerly winds will be a concern for new wind slab formation Wednesday.
Snowpack Summary
Roughly 25-35 cm of new snow fell in the region Monday night through Tuesday morning. It buried moderately wind-affected snow in exposed areas at elevation and otherwise added to about 50 cm of recent storm snow.
This older snow is settling and gradually bonding to a variety of old surfaces. Sheltered terrain where it buried surface hoar is where its bond is still under suspicion. It overlies a crust below about 1600 m.
Two additional surface hoar layers in the top 1.5 m of the snowpack are diminishing in importance. The deeper of the two likely has a robust crust above it below treeline.
The depth of the snowpack varies greatly throughout the region and weak basal facets are present at the base of the snowpack.
Weather Summary
Tuesday night
Cloudy with easing flurries bringing 5-10 cm of new snow. Southwest alpine wind shifting northwest, 5-15 km/h, easing.
Wednesday
Clearing, still mainly cloudy. Northwest alpine wind 5-15 km/h. Treeline temperature -16°C.
Thursday
Mainly sunny with a trace of new snow from overnight. Northeast alpine wind 10-25 km/h. Treeline temperature -29°C.
Friday
Sunny. North Alpine wind 5-10 km/h. Treeline temperature -30°C to -35°C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Avalanche Problems
Storm Slabs
Watch for signs of slab formation in the new snow, particularly in wind-affected areas and where buried surface hoar could be preserved (think sheltered openings at mid elevations).
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Deep Persistent Slabs
Basal facets remain a real concern in steep, rocky terrain and other alpine features with thin-to-thick snowpack transitions. Recent avalanche activity tells us this problem is still lurking out there.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3