Avalanche Forecast

Cold arctic air sits over the region with little change in weather conditions over the next few days.

MONDAY NIGHT: Mostly clear skies, no significant precipitation, light wind from the northwest, treeline temperatures around -20 C.

TUESDAY: Sunny with a few clouds, no precipitation, light wind from the north, treeline temperatures around -15 C.

WEDNESDAY: Mix of sun and cloud, no precipitation, moderate wind from the northeast with gusts to 50 km/h, treeline temperatures around -15 C.

THURSDAY: Cloudy, light flurries with 5 cm of low density snow, light to moderate wind from the northwest, treeline temperatures around -12 C.

Over the weekend there was evidence of wind slab avalanches becoming reactive at upper elevations. There were several small (size 1) human triggered slabs including this one from Gin Peak that illustrates how shifting wind patterns can form slabs in atypical locations.

Cornices are large and looming and have the potential to trigger large avalanches on slopes below. Several large (up to size 2) cornices have been both human-triggered and explosive-triggered this week.

It remains possible to human-trigger large persistent slab avalanches, particularly in shallow snowpack areas at treeline and low alpine elevations. On Friday, a large (size 2.5) persistent slab avalanche was skier-triggered in the backcountry near Blackcomb. It released 110 cm deep on the early December crust layer on a northwest facing slope around 2100 m in a shallow rocky start zone.

20 to 35 cm of low density snow can be found in many locations, although gusty conditions have been causing highly variable wind loading patterns. On Sunday, there were some reports of calm conditions in the alpine with minimal wind affect while neighbouring areas reported extensive wind affect. The current weather conditions could quickly form reactive slabs on leeward slopes, including unusual cross-loading or reverse-loading patterns in wind-exposed areas. Sensitivity to triggering will be greatest near ridge crests and roll-overs. Monitor for changing slab conditions as you move into wind-exposed terrain, and give cornices a wide berth.

A concerning weak layer of facets (sugary snow) can be found over a widespread crust that formed in early December (down 100-200 cm). This layer has been most reactive at treeline and low alpine elevations, between 1500-2100 m. Large (size 2-3) avalanches have been reported recently on this layer. This problem is particularly hard to predict and tricky to manage. Get more details and photos in our forecaster blog. 

• Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
• Be especially cautious near rock outcroppings, on steep convexities and anywhere the snowpack feels thinner than average.