North Columbia

Avalanche hazard will rise with incoming snow and increased winds.

Moderate - Intensity of incoming weather systems is uncertain.

WEDNESDAY NIGHT: Isolated flurries, up to 10cm accumulation. Moderate south wind. Freezing level 1000m. THURSDAY: Snow, accumulating 20-30cm, increasing through the day. Moderate south wind with extreme gusts. Freezing level rising to 1500m. FRIDAY: Cloudy with isolated flurries, up to 5cm accumulation. Moderate west wind gusting to strong. Freezing level dropping to valley bottom. SATURDAY: Cloudy with isolated flurries, up to 5cm accumulation. Light south wind. Freezing level valley bottom.

The storm snow continues to be reactive, on Tuesday several large (size 2-2.5) natural storm slab avalanches were reported. Additionally, a group of skiers remotely triggered a large (size 2.5) avalanche from about 100 m away, the avalanche failed on a layer of surface hoar down 80cm. Over the weekend, very large (size 3-3.5) natural and explosives triggered avalanches, and large (size 2-2.5) human triggered avalanches to size 2.5 were reported. Notably, several of these avalanches were triggered from a distance (remote triggered). On Friday, a very large (size 3-4) natural avalanche was reported to have run full path, burying a road under several meters of debris on the west side of Kinbasket Lake. This avalanche occurred in the northern reaches of the North Columbia region, close to the boundary of the Cariboo region. These full path avalanches can catch people by surprise, especially when there is very little snow in the valley bottoms. A report of this avalanche can be found on the Mountain Information Network here.

Recent storms have deposited 60-100cm of new snow. This new snow sits on a weak layer of facets (sugary snow), surface hoar (feathery crystals), and a sun crust (on south aspects). Strong winds have promoted widespread slab formation, particularly with the most recent new snow available for transport. A weak layer from mid November is now buried up to 150 cm and consists of surface hoar and a sun crust. The potential may exist for smaller avalanches to step down and trigger this deeper layer, resulting in large avalanches. The most likely place for this layer to be a problem is on steep, south facing slopes at treeline where the surface hoar sits on the sun crust. At the base of the snowpack is a crust that formed in late October. Concern for this layer is dwindling but it may still be worth considering in places such as steep, rocky, alpine terrain, especially where the snowpack is shallow. It would likely take a large trigger such as a cornice fall to produce an avalanche on this layer.