Avalanche Forecast
Regions: South Columbia.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Thursday: Light snow. 5-10cm. Light to moderate south-west winds. Freezing level valley floor.Friday/Saturday: Clear and sunny. Light winds. Afternoon temperatures rising on sunny slopes, with the freezing level falling to valley floor at night.
Avalanche Summary
On Tuesday, a number of size 1-1.5 avalanches were triggered in the storm snow naturally and by people. The frequency of deep releases on the February persistent weakness has gone down, with the most recent reports occurring at the weekend (size 3-3.5 slabs, 100-180 cm deep). There were also two size 3 avalanches that were triggered accidentally by snowmobilers just south of the region near Kimberley on Sunday. I'm concerned about strong solar warming on Friday and Saturday potentially triggering cornice fall or surface avalanches, which could step down to the Feb weakness, leading to very large releases.
Snowpack Summary
South to south-westerly winds combined with new snow have created wind slabs in the alpine and at treeline. Sunny periods on Sunday developed a sun-crust on southerly aspects up well into the alpine. Older storm snow is reported to be bonding well to underlying surfaces. A key concern is a persistent weak layer of buried surface hoar from mid-February that is buried 1-2 m deep. Snowpack tests give sudden "pops" results on this layer, indicating the ongoing potential for very large avalanches. Because the layer is so deeply buried, it's unlikely to fail without a large trigger (e.g. cornice fall or explosive). However, there's always the chance of someone stumbling across a sweet spot, particularly in shallow snowpack areas.
Avalanche Problems
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 4
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 3
Deep Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 3 - 9