Pockets of wind slabs are expected to be still reactive to human-triggering in exposed high elevation terrain, especially where they overlie a firm crust.
Recent strong northerly winds have retributed available snow and formed wind slabs in exposed terrain at higher elevations. These wind slabs may be still reactive, especially where they overlie a firm crust.
A weak layer from late-January is down 40-100 cm and was most reactive between 1700 and 2000 m in the north of the region. It is now likely dormant in most areas, especially where there is a supportive crust above. In the south of the region, a weak layer from mid-February under the recent storm snow is the more concerning buried weak layer.
A major weather pattern change takes place beginning this weekend. As the ridge of high pressure breaks down, this opens the door to a cascade of incoming Pacific weather systems.
FRIDAY NIGHT: Cloudy with clear periods, no precipitation, 15-30 km/h southerly wind, alpine low temperature -6 C, freezing level at valley bottom.
SATURDAY: Increasing cloudiness with isolated flurries in the late afternoon, 1 cm, 30-50 km/h southerly wind, alpine high temperature -1 C, freezing level at 1500 m.
SUNDAY: Periods of snow, 5-10 cm, 40-60 km/h southwesterly wind, alpine high temperature 0 C, freezing level at 1500 m.
MONDAY: Snow, 10-20 cm, 30-50 km/h southwesterly wind, alpine high temperature -1 C, freezing level at 1500 m.
On Thursday, several natural and human-triggered loose wet avalanches up to size 1.5 were reported on solar aspects. Several natural loose dry avalanches were also observed on steep north-west and east slopes. Finally, a few wind slab avalanches size 1.5 were triggered on east aspect in the alpine.
Recent northerly winds have redistributed available snow to form wind slabs in lee features and have scoured to the crust in exposed terrain. A sun crust is also found at the surface on solar aspects.
A weak crust layer from mid-February is now down around 20 cm in the north and as deep as 70 cm in the south. The melt-freeze crust is reported to exist on all aspects and elevations, except for high elevation northerly aspects in the north of the region. Facets and surface hoar can be found above the crust in the north of the region.
A weak crust/facet/surface hoar interface from late-January is buried down 40-100cm. This layer was most reactive between 1700 m and 2000 m in the north of the region. While this layer now appears to be dormant through most of the region, it may still be possible to trigger it at upper treeline or lower alpine features on northerly aspects in the north of the region with a large load like a cornice or in shallow snowpack areas.
