South 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 northerly wind with moderate gusts near ridgetop, trace of snow possible. FRIDAY: Scattered clouds at dawn with cloud cover building through the day, freezing level at valley bottom, light variable wind at valley bottom with moderate northwest wind in the alpine, 2 to 8 cm of new snow expected during the day with another 5 to 10 cm of snow Friday night.SATURDAY: Storm day, Overcast, freezing level beginning at valley bottom, rising to around 1500 m by sunset. Strong southwest wind, 8 to 20 cm of snow.SUNDAY: Broken cloud cover, freezing level at valley bottom, moderate north/northwest wind, trace of snow possible.

Avalanche activity has diminished over the last few days. On Wednesday reported activity was limited to a small wind slab on a west facing aspect at ridgecrest and reports of rather minor sluffing. No new avalanche activity was reported Tuesday. On Monday a few old size 2 natural avalanches were observed on south facing features between 1600 and 2300 m. The avalanche at 1600 m was notable as it was below treeline. The last reports of persistent slab avalanches came in on Saturday December 22nd.

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 60 to 120 cm deep. The layer is composed of 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.