A Special Public Avalanche Warning (SPAW) is in effect for this region. Natural avalanche activity will taper off somewhat on Saturday, but THE POTENTIAL FOR HUMAN TRIGGERED AVALANCHES REMAINS LIKELY.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
FRIDAY NIGHT - Cloudy with flurries, 5-10 cm / southwest winds , 35-60 km/h / alpine low temperature near -11SATURDAY - Cloudy with sunny periods and isolated flurries / south to southwest winds, 15-30 km/h / alpine high temperature near -9SUNDAY - Cloudy with sunny periods and isolated flurries / south to southwest winds, 20-50 km/h / freezing level 1400m / alpine high temperature near -2, low temperature near -8MONDAY - Mainly cloudy with flurries, 10-15 cm / south winds, 20-60 km/h / freezing level 1400m / alpine high temperature near -3, low temperature near -7
Avalanche Summary
Avalanche activity continues in the North Columbia region. The storm slab has been very reactive, producing both natural and human triggered avalanches up to size 2.5 on Thursday. Several of these avalanches were triggered from a distance (remote triggered). In the neighboring Glacier National Park region, artillery avalanche control produced size 2-3.5 avalanches on Thursday and Friday, many terminating near the bottom of their run out zones. Reports suggest that some of these may have stepped down to the mid November weak layer.On Friday, a size 4 natural avalanche was reported to have run full path, burying a road under several metres 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.
Snowpack Summary
60-90 cm of recent storm snow sits on a weak layer of facets (sugary snow), surface hoar (feathery crystals), and a sun crust (on south facing slopes). Strong winds have promoted widespread slab formation.A weak layer from mid November is now buried up to 150 cm and consists of surface hoar and a sun crust. While not recently reactive, 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.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.