Avalanche Forecast
Regions: Akamina, Bull, Crowsnest North, Crowsnest South, Elkford East, Elkford West, South Rockies.
The more supportive the surface crust, the more stable the snowpack. Keep up the conservative terrain choices at higher elevations where persistent slabs may still react to a human trigger.
Confidence
Moderate
Avalanche Summary
Natural size 2.5 persistent slabs were observed in the Castle area on Friday and again on Saturday. Friday's slide released from a cross-loaded gulley at treeline and both ran on the late-January weak layer, around 50 cm deep.
In nearby Warterton, five natural size 2.5 - 3 persistent slabs were observed on north through east slopes at treeline and in the alpine, one triggered by a cornice and all failing on the same January layer, which remains a concern at higher elevations.
Snowpack Summary
A melt-freeze crust or moist snow makes up the surface on solar aspects and on all aspects below about 1900 m. Moist snow extends 30 - 50 cm deep and thin solar aspects are moist to ground. This process has transformed 30 cm of snow from last week, which was 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 was active during the warmup and remains a concern at elevations where strong surface crust hasn't stabilized the snowpack.
Check out this MIN for recent conditions in the Elkford area.
Weather Summary
Sunday Night
Becoming cloudy. 5 to 20 km/h northwest ridgetop wind, increasing. Freezing level falling from 2700 m to 1500 m.
Monday
Cloudy with scattered flurries bringing about 5 cm of new snow above 1400 m. 15 - 20 km/h northeast ridgetop wind. Freezing level 1500 m. Treeline temperature -2 °C.
Tuesday
A mix of sun and cloud with cloud increasing. 5 - 15 km/h southwest ridgetop wind, closer to 40 km/h in alpine, increasing. Freezing level 1800 m. Treeline temperature around 0 °C.
Wednesday
A mix of sun and cloud with isolated flurries and cloud decreasing. 15 - 25 km/h southwest ridgetop wind, easing. Freezing level 1800 m. Treeline temperature around 0 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid thin areas like rocky outcrops where you're most likely to trigger avalanches on deep weak layers.
- Wind slabs are most reactive during their formation.
- Avalanche activity is unlikely when a thick melt-freeze crust is present on the snow surface.
Avalanche Problems
Persistent Slabs
The 40 - 60 cm-deep January weak layer has produced large avalanches in recent days remains a concern in areas where strong surface crusts are absent.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3
Wind Slabs
Small wind slabs may form in open terrain at higher elevations as new snow accumulates.
Aspects: South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1.5