Avalanche Forecast
Regions: Akamina, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West, South Rockies.
Skyrocketing alpine temperatures and a rotten snowpack structure are a recipe for large natural avalanches. Saturday will be a great day to soak up the sun outside of avalanche terrain.
Confidence
Moderate
Avalanche Summary
Two size 2 wind slabs were targeted with explosives on Wednesday in the Castle area. They featured 10 - 30 cm crowns that were noted for containing three distinct wind slab layers from recent loading events.
On Monday, explosives control in the same area produced avalanches to size 2 on east/southeast facing slopes. These involved both storm snow and the buried late-January weak layer, which is expected to remain reactive during the ongoing warmup.
Snowpack Summary
A melt-freeze crust moist or snow now glazes the surface on solar aspects and potentially to mountaintop by Saturday afternoon. High overnight freezing levels mean crust recovery may be weak. This process will affect around 30 cm of settling recent snow, which has been redistributed by strong southwest winds at treeline and above.
The main feature of the region's overall shallow snowpack is a persistent weak layer of surface hoar or facets from late January now buried 40 to 60 cm deep (see photo below). This layer is expected to be increasingly reactive as warming tests the snowpack.
Check out this MIN for recent conditions in the Elkford area.
Weather Summary
Friday Night
Partly cloudy. 15 to 20 km/h west ridgetop winds, easing. Freezing level falling from 2200 m to 1700 m.
Saturday
Becoming sunny. 15 to 20 km/h west ridgetop wind. Freezing level to 3300 m, remaining high overnight. Treeline temperature 6 °C.
Sunday
Sunny. 5 to 10 km/h west ridgetop wind, shifting northeast. Freezing level falling from 3000 m to 2600 m. Treeline temperature 7 °C.
Monday
Cloudy with scattered flurries bringing less than 5 cm of new snow above 1500 m. 15 - 25 km/h northeast ridgetop wind. Freezing level 1600 m. Treeline temperature -1 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Make conservative terrain choices and avoid overhead hazard.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Even brief periods of direct sun could produce natural avalanches.
Avalanche Problems
Persistent Slabs
A 40 - 60 cm-deep weak layer of large facets will face a serious test during the warmup on Saturday. Natural activity is expected.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1.5 - 3
Loose Wet
High freezing levels and solar warming will work to destabilize snow on steep slopes sheltered from the wind. Moist or wet snow may shed naturally or with a human trigger and loose releases may trigger more destructive slab avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1.5