Avalanche danger could spike to HIGH on any slopes which are getting baked by sun. Avoid traveling on, or underneath such areas.
Summary
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
Friday: Southern and eastern parts of the region may experience lingering cloud and flurries, while other areas could be warm and sunny. Generally light winds. Freezing level around 1000m.Saturday/Sunday: Sunny. Light southerly winds. Freezing level rising to around 1500m in the afternoon and falling to valley floor at night. On Sunday afternoon, freezing level is forecast to rise to around 2000m.
Avalanche Summary
On Wednesday, a size 3 slab failed on the mid-Feb weakness on a west aspect, with a 2 m deep crown. It was suspected that solar warming was the trigger. While avalanche activity on this layer is no longer widespread, large avalanches continue to occur on a sporadic basis. Last weekend, size 3-3.5 slabs, 100-180 cm deep, failed naturally and two size 3 avalanches were triggered accidentally by snowmobilers just south of the region near Kimberley. Solar warming may lead to another spike in deep persistent slab activity over the next few days. A number of size 1-1.5 storm slabs and wind slabs were also triggered naturally and by people over the last couple of days.
Snowpack Summary
Wind slabs in the alpine and at treeline are becoming less reactive. A melt-freeze crust exists from valley floor into the alpine on solar aspects. Older storm slabs are mainly 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 in some areas, 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.
pgoddard,
Avalanche Canada
