North Columbia

Large human triggered avalanches remain a possibility. Right now it's less about snow and more about human factors. The bold will push into bigger lines, those with lower risk threshold will be content with more conservative terrain. Fx'r blog here.

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Saturday

Friday offers another day of rather benign weather before the storm track takes over Saturday. The clouds begin to fade away Sunday giving way to what looks to be a pretty robust ridge of high pressure that we will ride into the New Year.THURSDAY NIGHT: Freezing level at valley bottom, light west/northwest wind with moderate gusts near ridgetop, trace of snow possible. FRIDAY: Broken cloud cover at dawn building to overcast by sundown, freezing level at valley bottom, light southerly wind at valley bottom with moderate southwest wind in the alpine, trace of snow possible during the day with 5 to 10 cm expected Friday night.SATURDAY: Storm day, Overcast, freezing level beginning at valley bottom, rising to around 1600 m by sunset. Strong to extreme southwest wind, 10 to 20 cm of snow.SUNDAY: Broken cloud cover, freezing level at valley bottom, moderate north/northwest wind, trace of snow possible. 

Avalanche activity on Wednesday was limited to a few small wind slabs pried out by explosive control work near ridgecrest.  No new avalanche activity to report from Tuesday aside from minor sluffing. Monday was similar with riders triggering small loose dry avalanches in steep terrain as the storm snow sluffed away. The last reported persistent slab activity was on Sunday when a few large (size 3) persistent slab avalanches were observed on south facing alpine features.  This was the finally of a widespread persistent slab avalanche cycle that was quite active last week, particularly in the Selkirks and the northern tip of the Monashees.

10 to 20 cm of low density snow sits above old wind slabs in the alpine, and in some isolated areas above small surface hoar (feathery crystals).A weak layer that formed during the dry spell in early December is now 80 to 120 cm deep. The layer is composed of weak facets, surface hoar, and a sun crust on steep south-facing slopes. This layer was previously responsible for large persistent slab avalanches, but activity has greatly diminished over the last week. Saturday's storm may breathe some life into it, the places of greatest concern will be north and east facing slopes between 1900-2300 m and steep south-facing slopes in the alpine.The lower snowpack is generally strong and settled, with a crust that formed in late October near the bottom of the snowpack.