Regions
Northwest Inland.
Large destructive avalanches remain likely due to ongoing snow, rain, wind, and warming. Stick to mellow terrain and avoid overhead hazards.
Confidence
Moderate - Forecast snowfall amounts are uncertain on Tuesday
Weather Forecast
MONDAY NIGHT: Scattered flurries with up to 5 cm of new snow, strong southwest winds, freezing level around 700 m. TUESDAY: Another storm pulse brings 5-15 of new snow, strong southwest winds, freezing level around 1100 m.WEDNESDAY: Flurries with up to 5 cm of new snow, moderate southwest winds, freezing level around 1000 m.THURSDAY: Clearing with isolated flurries, moderate southwest winds, freezing level around 800 m.
Avalanche Summary
Poor visibility has limited avalanche observations during the storm. Recent reports include a size 1 skier triggered storm slab near Kispiox and an audible natural avalanche in the southwest part of the region.Triggering storms slab avalanches will remain likely in areas that receive heavier snowfall over the next few days. However, the primary concern throughout the region is the deep persistent slab problem, as large destructive avalanches remain likely with ongoing warming and loading.
Snowpack Summary
Expect another 10-20 cm of new snow by Tuesday, bringing recent storm snow totals to 20-40 cm in the southern part of the region. With strong winds and rising freezing levels, expect touchy storm slabs throughout the week. The new snow has buried a layer of feathery surface hoar crystals, which will allow for wide propagations in the storm snow.Snow depths at treeline vary from about 1 m in most areas to 2 m in deeper snowpack areas in the south and west of the region. The shallow snowpack areas mostly consist of weak faceted or sugary grains beneath hard slabs. With the additional load of new snow and rain, these hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak faceted snow near the ground.
Problems
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.
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.