South Columbia

Tricky conditions are expected on Wednesday with warm temperatures continuing, strong winds in the alpine, and new snow/rain. Use a conservative approach and avoid avalanche terrain during periods of rainfall.

Moderate - Timing, track, or intensity of incoming weather system is uncertain

A warm storm system reaches the interior on Wednesday morning. 5-10 mm of precipitation is expected during the day on Wednesday with freezing levels around 2500 m in the morning falling to 2000 m in the afternoon. Alpine wind is forecast to be moderate to strong from the southwest. Another 10-20 mm of precipitation is forecast for Wednesday overnight through Thursday afternoon. Freezing levels are forecast to remain around 2000 m on Thursday and alpine wind is forecast to remain moderate to strong from the southwest. Light precipitation is currently forecast to continue Thursday overnight and taper off Friday morning. Friday is forecast to be mostly dry and sunny with freezing levels falling to around 1500 m.

On Monday, natural loose wet avalanches up to size 2 were reported throughout the region from steep sun exposed slopes. A natural size 3 was reported on a northeast aspect at 2500 m and a natural cornice release triggered a size 2 slab on a southeast aspect at 2500 m. A skier also remotely triggered a size 1.5 wind slab on an east aspect at 2400 m which was triggered from 20 m away. On Sunday, a few natural wind slabs were observed in the alpine. A MIN report describes a remotely triggered size 3 avalanche on London Ridge. Click here for more details. On Wednesday, rain at lower elevations is expected to destabilize the upper snowpack resulting loose wet sluffing and potentially increasing the sensitivity of triggering persistent slab avalanches. In the alpine, new snow and strong southwest winds will likely form touchy new wind slabs. Wind slab avalanches have the potential to step down and trigger persistent slab avalanches.

The storm snow from last week has settled rapidly due to the recent mild temperatures. The snow surface is expected to have undergoing melting on Tuesday afternoon on sun exposed slopes. Recent strong winds from the south and west had redistributed the recent storm snow in exposed terrain forming wind slabs. The early February weak layer is typically down 50-80 cm and includes a sun crust on steep sun-exposed slopes, faceted snow, as well as surface hoar on sheltered open slopes. This layer has remained reactive recently and has been the main sliding layer for most of the recent slab avalanche activity. The mid and lower snowpack are generally well settled and stable in deeper snowpack areas but may be faceted and weaker in shallower areas.