Conditions vary greatly throughout the region with >60cm of new snow in the Coquihalla and much less further north. Local observations are crucial for safe backcountry travel.
Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Thursday: Cloudy with flurries - 2-5cm on average with more possible in the southeast corner. The freezing level rises to around 800-1000m during the day. Winds are light and variable. Friday: A mix of sun and cloud. Freezing level staying low near 800m. Winds remain light. Saturday: Mainly sunny and milder with the freezing level jumping to 1500m. Winds are light from the southeast.
Avalanche Summary
Currently the Coquihalla highway is closed for avalanche control. Areas north of Pemberton reported several skier controlled avalanches up to Size 1.5 within the recent storm snow (15-25cm crowns) on Tuesday. There was also one report of a larger avalanche in the South Chilcotin that may have failed on the mid-Feb persistent weakness.
Snowpack Summary
Conditions vary greatly throughout the region. Southeast areas (Coquihalla) have seen up to 60cm of new snow in the past 48 hours, while places like the Duffy Lake have seen considerably less. Expect new wind slabs to be deep in heavy snowfall areas and thin in other areas. Crusts down around 60cm can be found on solar aspects in the Duffey Lake, Chilcotin, and down closer to 1m in the Coquihalla. These exhibit moderate to hard, sudden results in snowpack tests. Deeper persistent weak layers are variable in distribution across the region. A crust/surface hoar/facet layer buried in early February, now down about 1.5m, is still is a key concern. It is especially prevalent on south-facing slopes above treeline, and all slopes below treeline. Although the likelihood of triggering this layer has decreased, the potential for surprisingly large avalanches remains. Cornices are reported to be very large and should be given a wide berth.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.