Purcells

The snowpack in the Purcells remains spooky with a persistent weak layer still very much in play. Conservative terrain choices are the ticket right now. Read more in the new forecaster blog here.

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Enjoy the brief lull in the weather Thursday and Friday, it looks like we will be right back into the storm track this weekend. What happens beyond that is a bit uncertain, but a ridge of high pressure will likely take us into the New Year.WEDNESDAY NIGHT: Freezing level at valley bottom, light variable wind, trace of snow possible. THURSDAY: Broken cloud cover, freezing level at valley bottom, light northerly wind, no significant precipitation expected. FRIDAY: Scattered clouds at dawn with cloud cover building through the day, freezing level at valley bottom, light southwest wind at valley bottom, light northwest wind in the alpine, trace of snow possible during the day. 1 to 5 cm of snow possible Friday night.SATURDAY: Overcast, freezing level beginning at valley bottom, rising to around 1600 m by sunset. Moderate to strong west/southwest wind, 2 to 10 cm of snow.

Control work Monday and Tuesday 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. Over the weekend explosives 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 50 to 100 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 80 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 over the past week. 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).