Avalanche Forecast

High -

Friday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light from the southwest. Freezing level of 800 metres with alpine temperatures around -8. Saturday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light to moderate from the northwest. Freezing level to 600 metres with alpine temperatures of -9. Sunday: Flurries bringing 5-10 cm of new snow. Winds light from the south. Freezing level to 800 metres with alpine temperatures of -8.

A MIN report from Wednesday details a skier triggered Size 1.5 slab avalanche occurrence on a southwest aspect in the Evening Ridge area. With a depth of approximately 8 inches it is suspected to have failed on a mid-storm interface layer. Loose dry avalanches were also observed running to Size 1.5 on Wednesday, both naturally from steep solar aspects as well as under skier traffic on steep north aspects.Reports from Tuesday included a skier-triggered Size 2 storm slab occurring on a southwest aspect south of Nelson, as well as numerous explosives controlled storm slabs ranging from Size 1.5-2 running on north and northwest aspects. Crown depths averaged around 20 cm, but were also noted as deep as 50 cm.For Friday, expect our storm slab problem to remain in the realm of human-triggering and particularly touchy in wind affected areas. Storm slabs may fail on a storm interface or could release a bit deeper on the widespread crust layer. Deeper instabilities in the snowpack also remain an isolated concern, meaning that storm slab avalanches have the potential to step down to deeper layers and result in very large avalanches.

At higher elevations, 30-50 cm of recent snow overlies a series of crust layers from mid-February. Recent reports suggest this snow is generally well bonded to the crust. On high north aspects, a layer of surface hoar from mid-February may sit below the recent snow and may still be reactive. In exposed terrain, recent southerly winds have scoured the new snow down to the crust and formed wind slabs in leeward features. The early-February surface hoar layer is now down approximately 80-100 cm. This layer was reactive during the warm storm last week but now appears to have gone dormant. Areas with a shallow snowpack (less than around 150 cm) generally have a weak snowpack structure with a layer of sugary facets near the ground.