Weak layers in the mid and lower snowpack have produced large natural and human-triggered avalanches in recent days.
Manage this problem with conservative terrain choices.
Recent strong southerly winds have formed wind slabs on a variety of aspects in lee features in the alpine and treeline.
If triggered, wind slabs have the potential to step down to deeper layers, creating a larger that expected avalanche.
A layer of surface hoar is down 50 to 90 cm and is still concerning where a significant crust is not found above it.
A weak layer of basal facets has produced large natural and human-triggered avalanches in recent days. This problem is most likely to be an issue in shallow snowpack areas in the alpine.
A natural avalanche cycle occurred last Friday. Several large (size 2 to 3) storm slab, persistent slab, and deep persistent slabs were reported from the alpine and treeline.
Over the weekend, many large (size 2 to 3) natural and rider triggered (some remotely triggered) persistent and deep persistent slabs were reported in the alpine and treeline.
Moving forward, natural avalanche activity has tapered, but large human-triggered slabs remain possible.
Recent strong winds have created heavily wind-affected surfaces in the alpine and treeline. Below treeline a new crust is on or near the surface.
The mid pack contains several layers of note; a layer of surface hoar and a crust down 20 to 40 cm, a significant crust from the early December rain event down around 50 cm and a layer of surface hoar down 50 to 90 cm.
The make up of the lower snowpack is variable throughout the region, in shallower snowpack areas, basal facets exist. This is most concerning in shallow alpine areas.
Tuesday Night
Clearing. Southwest alpine wind 50 km/h dropping to 20 km/h. Treeline temperature -5 °C. Freezing level dropping to valley bottom.
Wednesday
A mix of sun and cloud. South alpine wind 20 to 40 km/h. Treeline temperature -3 °C. Freezing level rising to 500 to 1000 m.
Thursday
Cloudy with snowfall, 1 to 5 cm of accumulation. Southwest alpine wind 20 to 50 km/h. Treeline temperature -2 °C. Freezing level 500 to 1500 m.
Friday
A mix of sun and cloud with isolated flurries. South alpine wind 20 to 40 km/h. Treeline temperature -3 °C. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
