A deeply buried weak layer means human-triggered avalanches will persist. Conservative decision making remains critical. Check out skiinggolden.com for a great video on the current conditions.
Confidence
Poor - Due to the number of field observations
Weather Forecast
A weak disturbance will bring increased cloud and light scattered flurries for Monday. Clear, dry conditions should return for Tuesday and Wednesday.Monday: A mix of sun and cloud, light flurries 0-1cm, treeline temperature around -18, light-moderate W alpine wind.Tuesday: Sunny, treeline temperature around -15, moderate-strong NW alpine wind.Wednesday: Sunny, treeline temperature around -12, light W alpine wind.
Avalanche Summary
Widespread natural activity up to size 3 was reported on Friday around Golden. Remote triggering from up to 50m away was also reported. Slabs were up to 1m deep and avalanches were running full path. On Saturday, avalanche control produce numerous more avalanches up to size 3. Check out skiinggolden.com for an impressive video of avalanche control on Saturday.Widespread natural activity up to size 3 was reported on Sunday in the Invermere area. This occurred between Thursday and Saturday. Explosives and ski cuts on Sunday produced several size 1 avalanches in previously controlled terrain.
Snowpack Summary
The storm produced slabs up to 1m thick in the north of the region and around 60cm thick in the south. This slab sits on the mid-November weak layer (surface hoar, facets, and/or a crust). Below this you will likely find a 15-20cm thick layer of sugary facets, which is sitting on a solid rain crust from early November. Reports of whumphing and remote triggering on these layers suggests a persistent weakness with the potential for large propagation and large avalanches. Recent strong and variable winds have likely created dense wind slabs in exposed terrain and resulted in variable snow distribution in the alpine. On Thursday, high elevation rain produced a new crust. In the Golden area this rain crust exists up to around 1600m whereas in the south it is up to 2000m or higher. As temperatures dropped, 10-20cm of new snow fell on top of this new crust.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.