Keep an eye on those cornices! One more sunny day of exploring before the clouds roll in. Bring sharp tools for the crust and start and finish early to avoid getting caught in isothermal snow.
Large cornices still loom over many ridgelines and they won't hang on forever. Be aware of these overhead hazards and stay well back from overhanging cornices on ridgelines.
Slushy, isothermal snow conditions often emerge on directly sun-facing slopes during the heat of the day. Plan your route with this in mind to avoid getting surprised by difficult travel and rising wet loose avalanche danger.
A cornice-triggered slab avalanche was observed from a distance on Overlord Mountain on Wednesday. It happened on a northwest aspect at 2400 m.
Activity has generally quieted since last weekend's warmup. Several more natural wet loose avalanches up to size 2.5 were observed in the Whistler area Monday, focused on west aspects above 2000 m. Ski cutting produced several size 1.5 releases. A bit less of the same type of activity was reported Tuesday.
Spring-like melt-freeze cycles now characterize a daily evolution of surface conditions on all but north-facing slopes above 2000 m, where 10 to 20 cm of windblown dry snow may still be found. Below this elevation and on solar aspects, the surface crust is 5 - 10 cm thick.
A crust/facet layer from late March sits 20 to 80 cm deep and another thick crust sits 80-100 cm deep. Near Whistler, some facets have been reported around the deeper crust. Neither of these layers are an avalanche problem right now, but they perhaps give large cornice falls from high north aspects a slim chance of triggering a slab, such as the one observed on Overlord Mountain on Wednesday.
The snowpack below is well settled and strong.
Thursday Night
Clear skies. 10 km/h south ridgetop wind. Treeline temperature 5 °C. Freezing level 2600 m.
Friday
Sunny, cloud increasing near end-of-day. 10 to 15 km/h southeast ridgetop wind. Treeline high temperature 7 °C. Freezing level 2600 m.
Saturday
Mostly cloudy with isolated showers, less than 1 mm. 5 to 10 km/h southwest ridgetop wind. Treeline high temperature 5 °C. Freezing level 2300 m.
Sunday
Mostly cloudy with light rain, 2 to 3 mm, and a possible trace of new snow in the alpine. 10 km/h variable ridgetop wind. Treeline high temperature 6 °C. Freezing level 2400 m.
More details can be found in the Mountain Weather Forecast.
