Avalanche Forecast

Low - 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, freezing level at valley bottom, light variable wind at valley bottom with moderate northwest wind in the alpine, trace of new snow possible during the day with 1 to 5 cm of snow expected Friday nightSATURDAY: Storm day, Overcast, freezing level beginning at valley bottom, rising to around 1600 m by sunset. Strong southwest wind, 5 to 10 cm of snow.SUNDAY: Broken cloud cover, freezing level at valley bottom, light north/northwest wind, trace of snow possible.

Avalanche control work on Wednesday produced avalanches to size 2 on north facing terrain between 1900 and 2400 m. On Monday and Tuesday control work produced avalanches to size 3 on steep north, northwest and northeast facing features between 1900 and 2700 m. One of the more interesting results was a size 1.5 wind slab that was remote triggered from 200 m away on a north facing slope around 2100 m. No new natural avalanche activity to report. On Sunday, a large (size 2.5) persistent slab avalanche was triggered by a snowmobiler in Silent Pass. The avalanche occurred on a wind loaded northwest-facing slope in the alpine. See details in the MIN report. Last weekend explosive control work produced numerous large persistent slab avalanches (size 2-4) in alpine terrain. The avalanches occurred on all aspects and failed on several different weak layers including the early December weak layer and weak facets at the bottom of the snowpack. Over the past two weeks, several large persistent slab avalanches were remotely triggered from skiers on adjacent slopes, particularly in the Golden area. There's a great summary of recent avalanche activity from SkiingGolden here.

5 to 15 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 110 cm deep. The layer is composed of facets (sugary snow), surface hoar (feathery crystals), and a sun crust (on south aspects). Another similar weak layer is buried 90 to 150 cm. Finally, the base of the snowpack has weak faceted layers at alpine and treeline elevations. All of these weak layers have been producing large avalanches as recently as December 25th. Human triggering any of these layers is most likely on slopes that didn't previously avalanche and on slopes that have variable snowpack depth (such as rocky alpine features).