Another day of dramatic, sustained warming should keep persistent slabs near their tipping point. Enjoy the balmy temperatures in low consequence terrain.
A reactive, 40 - 60 cm-deep weak layer of large facets has regularly produced large avalanches in recent days, partially as result of warming temperatures, which will continue through Sunday.
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.
A natural size 2.5 persistent slab was observed in the Castle area on Friday. It released from a cross-loaded gulley at treeline and ran on the late-January weak layer, 50 cm deep in this instance.
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 is expected to remain reactive throughout the ongoing warmup.
A melt-freeze crust or moist snow likely makes up the surface on all but high elevation north aspects. High overnight freezing levels mean crust recovery may be weak. This crust tops the upper part of 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 remain reactive throughout the weekend warmup.
Check out this MIN for recent conditions in the Elkford area.
Saturday Night
Clear. 10 to 20 km/h west ridgetop wind, up to 40 km/h in alpine, easing. Freezing level peaking at 3400 m.
Sunday
Sunny with cloud increasing in the evening. 0 to 10 km/h west ridgetop wind, shifting northeast late in the day. Freezing level falling from 3300 m to 2700 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 1500 m. Treeline temperature -1 °C.
Tuesday
Sunny. 5 - 15 km/h west ridgetop wind. Freezing level 1800 m. Treeline temperature around 0 °C.
More details can be found in the Mountain Weather Forecast.
