Regions
Northwest Inland.
It's time to reign the terrain choices way in. Stick to simple terrain free of overhead hazard. The potential for large destructive avalanches is significant as snow, warm temps and strong wind continue to impact the region through the weekend.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
The NW Inland is expected to remain dark & stormy for the forecast period as high-energy systems continue to impact the NW Coast and spill into the mountains of the interior.SUNDAY: Freezing level around 1000m, 5 to 15cm of snow expected with the bulk of the snowfall occurring Sunday night, strong southwest wind. MONDAY: Freezing level around 1300m, 5 to 10cm of snow, strong to extreme southwest wind. TUESDAY: Freezing level around 1500m, moderate to strong southwest wind, no significant precipitation.
Avalanche Summary
Deep persistent slab avalanches continue to be reported in the Ningunsaw area, including natural and explosive triggered size 2.5 avalanches running on basal facets on southwest aspects. A natural size 2 wind slab avalanche was reported in the southern part of the region on Thursday, releasing on a wind-loaded northeast alpine slope.As the storm cycle continues, we can expect an increase in avalanche activity, including very touchy storm slabs that have the potential to trigger large deep persistent slab avalanches.
Snowpack Summary
5 to 30 cm of snow fell Friday night into Saturday accompanied by light to moderate southwest wind and warm temperatures. This new snow is expected to form a widespread storm slab problem that should be very touchy on lee features at all elevations. The new snow is burying a layer of feathery surface hoar crystals, which will likely allow for wide propagations in the storm snow. Snow depth at treeline varies 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 these hard slabs may produce surprisingly long fractures resulting in large avalanches, and in some instances they may step down to weak faceted snow crystals 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.