Continued snowfall and wind will keep storm slabs fresh Saturday. In areas that receive less than 10 cm of new snow, avalanche danger may be a step lower at treeline and below.
30-80 cm sits on a buried weak layer that consists of facets, surface hoar, or a crust, depending on location. Avalanches on this layer may propagate widely.
Storm slabs will likely continue to be reactive, especially in wind loaded areas and in places that see more than 15 cm of new snow over the day Saturday.
Friday night: Cloudy with a few flurries up to 5 cm, moderate to strong westerly ridgetop wind, alpine temperature -8.
Saturday: Snow, around 5 cm in the north and up to 20 in the south, light to moderate westerly ridgetop wind, alpine high -8, freezing level 800 m in the north, 1300 m in the south.
Sunday: Mix of sun and cloud, light variable wind, alpine high -10, freezing level valley bottom.
Monday: Mix of sun and cloud, light variable wind, alpine high -13, freezing level valley bottom.
Loose wet avalanches up to size 2 were reported on Friday, triggered by the sun and running on a shallow crust. Skier triggered wind slabs up to size 1 were reported on Thursday. Throughout the week, there have been reports of natural, explosive and human triggered avalanches size 1-2, including a widespread natural avalanche cycle Monday night. Many of these failed on the recently buried persistent weak layer.
In the south, hot spots around Hope are forecast to receive as much as 20 cm of new snow over the day. In combination with westerly wind, this new snow is likely forming reactive storm slabs in the alpine and open treeline areas. In the north, localized wind slabs are forming over a crust on solar aspects as westerly winds redistribute recent snow into leeward terrain features.
30-80 cm of recent snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1600 m, and a sun crust on south-facing slopes.
In the south, the underlying snowpack is well consolidated. In the north, a melt-freeze crust from early December may be found 100 to 200 cm deep. Recent reports suggest that this layer is gaining strength and it has been unreactive in recent weeks.
