Regions
Northwest Inland.
Reports from the region have been limited and it is essential to supplement this forecast with your own observations as well as conservative travel techniques. Please post your observations to the Mountain Information Network. (MIN)
Confidence
Low - Due to the number of field observations
Weather Forecast
Sunday: Cloudy with flurries bringing approximately 7 cm of new snow. Moderate southeast winds. Alpine temperatures of -5.Monday: Mainly cloudy with isolated flurries and a trace of new snow, increasing in the evening. Strong southwest winds. Alpine temperatures around -6.Tuesday: Mainly cloudy with scattered flurries bringing approximately 5 cm of new snow. Moderate to strong southwest winds. Freezing level rising to 1300 metres with alpine temperatures around -3.
Avalanche Summary
One report from Wednesday discussed several estimated Size 2.5-3 avalanches observed on the Kathlyn face of Hudson Bay Mountain. A recent report from social media showed a Size 2 avalanche that occurred last Monday in alpine terrain in the Babines. In spite of its age, the slide is notable for apparently having run on the late October persistent weak layer. No other new avalanches have been reported. Please post your observations to the Mountain Information Network. (MIN)
Snowpack Summary
Snowpack depths over the south of the region are above average for late November, with approximately 150 cm of settled snow present at treeline elevations and above. Stormy weather last week delivered about 40 cm of new snow to the region and there is a good likelihood of wind slabs remaining reactive in open terrain where wind effects were more pronounced during and since the storm. Mid-treeline and lower elevations did receive some precipitation as rain toward the end of the storm, but the thin crust that resulted is not expected to offer bridging strength to the snowpack. About 20-30 cm of settled storm snow lies below last week's accumulations and above the widespread late October crust. This October crust is present near the base of the snowpack at all elevations and features a layer of weak, sugary grains above it. This "crust/facet combo" layer remains an ongoing concern for step-down potential from large triggers such as a storm slab release. The crust is less of a concern below treeline where it is broken up by vegetation near the ground.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.