Summary
Confidence
Fair - Freezing levels are uncertain on Saturday
Weather Forecast
High pressure is expected to continue to dominate the interior until the middle of next week. Warm air that is trapped above about 2100 metres continues to cause above freezing temperatures, sunny skies, and valley cloud. Valley temperatures are expected to drop below freezing overnight. The inversion may continue until Sunday. If the valley cloud clears, then we should get a good freeze in the alpine.
Avalanche Summary
Explosive control in the Kaslo to New Denver highway corridor on Thursday produced several size 2.5 moist releases that pushed storm snow to the middle of the runout of 2 km long paths. These slides started between 2000 and 2300 metres on S-SW aspects. A larger explosive controlled avalanche occurred at Bear Lake from a SE aspect in the alpine. The avalanche was size 3.5 dry slab with an average crown of 160 cm and ran full path, 1100 vertical metres for 2.5 km. Reports of loose dry sloughing in steep terrain from several operators in the area up to size 1.5. Explosive control at Kootenay Pass produced several avalanches size 2.5-3.0 on cross loaded slopes with crowns between 50-100 cm.
Snowpack Summary
New sun crusts are developing on steep solar aspects. Warm air trapped in the alpine caused temperatures to remain above freezing on Thursday night above about 2100 metres. Pin-wheeling and other signs of moist snow have been observed on solar aspects at and above treeline. Continued warm temperatures in the alpine may trigger buried weak layers on solar aspects. Steep planar slopes with shallow snowpacks are the most suspect. The recent storm snow layer is about 30-50 cm thick and is quite variable across the region. There are a couple of thin crusts buried below the storm snow that have been producing moderate to hard shears in tests. Some areas are still getting sudden planar shears on the mid-december surface hoar layer.
triley,
Avalanche Canada
