A large amount of recent storm snow rests on weak layers, making the snowpack complex.
Uncertainty is best managed through conservative terrain choices.
Weak layers remain a concern in north-facing terrain where snowpack depth is variable. These layers are still adjusting to the new snow load and may be reactive to human-triggering.
Continuous storms in the past week have left numerous storm slab interfaces in the top 80 cm of the snowpack with deeper deposits in wind-loaded terrain.
On Saturday, a persistent slab (size 2) avalanche was observed on the Duffey Lake road. It naturally failed on the early March persistent weak layer, with a step-down to the mid-February weak layer.
On Friday, numerous solar-induced avalanches were reported in the Birkenhead region, with a notable persistent slab avalanche (size 3.5) that ran full path on a northeasterly alpine slope.
North-facing alpine and treeline terrain are seeing continued avalanche activity.
An additional 5 cm is expected on Saturday night, which will bring this week's storm totals to 80 to 150 cm of new snow. This sits on a weak layer formed in early March that consists of facets or surface hoar that overlie a crust on all aspects except high north-facing slopes.
Weak layers formed in mid-February and late-January are now buried 80 to 175 cm deep.
Saturday Night
Cloudy with up to 5 cm of new snow. 30 to 50 km/h southwest ridgetop wind. Treeline temperature -10 C. Freezing level at valley bottom.
Sunday
Partly cloudy. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -4°C. Freezing level 1200 m.
Monday
Mostly cloudy with isolated flurries. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level rising to 1200 m.
Tuesday
A mix of sun and clouds. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -6 °C. Freezing level 1000 m.
More details can be found in the Mountain Weather Forecast.
