Be mindful that persistent instabilities are highly unpredictable and are still a concern.
It requires a patient and diligent mindset to keep avoiding steep, rocky, wind-affected terrain.
Lingering weak layers are present at all elevations and on various aspects. On shaded slopes, these layers generally present as surface hoar or facets, while on sun-exposed slopes, they appear as facets and a crust.
The base of the snowpack remains very weak. Very large human-triggered avalanches are possible at treeline and above. Avoid thin, rocky start zones and shallow areas with variable snowpack depth where you are most likely to trigger this layer. Give careful consideration to the slopes overhead as large avalanches may run well into the runout zone or into lower-angle terrain.
Numerous natural dry loose avalanches (size 1) were observed within the recent snow on steep northerly alpine terrain in the south part of the region on Saturday.
Earlier in the week, several occurrences of very large deep persistent slabs (size 2.5 and 3) were observed on south aspects, from rocky alpine and treeline features between 1900 and 2700 m. These were triggered naturally by strong solar radiation, and some released to the ground. A natural step-down avalanche, involving the mid-snowpack persistent weak layer, was also reported on a south-facing slope near Panorama Ski Resort on Wednesday. A remotely triggered persistent slab avalanche was reported last Sunday, failing down 70 cm on facets and triggered from 30 m away on a NW alpine slope.
While recent activity may seem to have tapered off, remote and step-down avalanches are a reminder that the layers are likely still reactive in some locations in the region, especially thin, rocky areas in the alpine.
At upper elevations, a dusting of new snow overlies a crust on solar aspects, faceted snow and surface hoar (up to 10 mm) in shaded and wind-sheltered areas. Wind-affected surfaces is also found in exposed areas.
In the middle of the snowpack, there are at least a couple of lingering persistent weak layers, including surface hoar in wind-sheltered terrain and a sun crust on south aspects. Activity on these layers has tapered off but still remains a concern in isolated areas.
The lower snowpack is made up of a widespread layer of large, weak facets and/or depth hoar crystals. This weak layer has been responsible for a number of recent very large, destructive avalanches and will likely continue to be a concern for the rest of the season.
Unsettled weather will continue to bring scattered flurries until a ridge of high pressure invades the region early next week.
Sunday night
Cloudy with clear periods. Isolated flurries with trace accumulation. Low alpine temperatures of -6 °C. Light westerly ridge wind. Freezing level at valley bottom.
Monday
Cloudy. Isolated convective flurries. Local amounts up to 5 cm. High alpine temperatures of -6 °C. Light westerly ridge wind gusting 25 km/h. Freezing level rises to 1300 metres.
Tuesday
A mix of sun and clouds. High alpine temperatures of -5 °C. Light easterly ridge wind. Freezing level rises to 1400 metres.
Wednesday
Sunny with cloudy periods. High alpine temperatures of -3 °C. Light easterly ridge wind. Freezing level rises to 1800 metres.
More details can be found in the Mountain Weather Forecast.
