Avalanche Forecast

THURSDAY: Freezing level: 1900m, mix of sun and cloud, light variable ridgetop winds. FRIDAY: Freezing level: 1700m, mostly sunny,  light southerly ridgetop winds. SATURDAY: Freezing level: 2500m, mix of sun and cloud, light southerly ridgetop winds.

No new avalanches were reported in this region on Tuesday. However, with the recent snow and wind I would expect to find thin wind slabs ripe for human triggers on lee features in the alpine on Thursday.

Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. There is an old crust layer down approximately 50cm in the Duffey area and north of Pemberton. This layer has generally been dormant but resulted in a couple large avalanches during the last major warming event and produced a couple explosive triggered avalanches on Thursday. With continued warming, this layer could wake-up in isolated locations such as steep, rocky faces. Glide cracks are widespread, active, and best avoided. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day, especially on steep, rocky faces.