Avalanche Forecast

Good

Wednesday: Another 15-25cm of snow is expected with freezing levels rising as high as 1800m and strong southwest winds. Thursday: 20-30cm of new snow or more for immediate coastal areas, with freezing levels around 1600m and light to moderate southeasterly winds. Friday: Continued snowfall with another 5-10cm of accumulation, or more for immediate coastal areas. Freezing levels dropping to 1200m and moderate southwesterly winds.

Reports from Tuesday include numerous Size 1.0 to 2.0 storm slab avalanches running easily on recently buried surface hoar and sun crust at treeline and alpine elevations. Most avalanches were human-triggered with explosives or slope-cuts but a few naturals were observed in the afternoon out of steep rocky treeline terrain with a temperature spike. Numerous natural loose moist avalanche up to Size 2 were also observed on all aspects at treeline and below in a coastal area.

Approximately 30cm of new snow had already fallen by Tuesday morning and another 20-30cm is expected by the end of the day. This new snow is bonding poorly to the previous snow surface, which includes faceted snow, surface hoar, and/or a crust, but is most concerning where surface hoar is sitting on a crust on previously sun-exposed sheltered treeline slopes. Around a metre below the snow surface is a layer surface hoar buried on February 20th. Although this layer has a history of producing large avalanches, triggering this layer has now become difficult, and would most likely require a very large trigger on a steep, unsupported slope. Below this interface, the snowpack is strong and well settled.