The warm, wet, windy storm continues. Backcountry ski conditions are reported to be terrible and avalanche hazard remains elevated. Now is a good time for indoor activities or take your rain gear with you to your local ski hill.
Confidence
Poor - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The storm system continues to bring warm, wet conditions to the interior for Wednesday and Thursday. The Purcells region can expect another 5-10mm on Wednesday and 10-15mm for Thursday. Freezing levels on both days are expected to be 2200-2500m. Alpine winds should remain strong but might start to taper off late-Thursday. On a positive note, things should start to change on Friday. Freezing levels should drop, winds should ease, and we may see new snow at higher elevations.
Avalanche Summary
Limited observations on Tuesday includes a report of explosive triggered slabs up to size 1.5 in the Golden area. Also reported was small loose wet activity in the Invermere area.
Snowpack Summary
New moist or wet snowfall sits 10-20cm above a layer of surface hoar. Another 15-20cm below this you may find a hard rain crust. In the Golden area this crust exists up to around 1600m, whereas in the south it is up to 2000m or higher. In total, last week's 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. The reactivity of these layers may be slowly diminishing, but they still warrant cautious consideration. Snowpack tests are getting hard pops and drops results, indicating the potential for large propagation and large avalanches.
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.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.