Spring Conditions. Record breaking warm weather continues. Expect the likelihood of wet slab avalanches, cornice falls, and loose wet avalanches to increase during the heat of the day.
Summary
Weather Forecast
Clear overnight with light southwest winds and freezing levels around 2000 metres. Clear and sunny on Wednesday with light winds and daytime freezing up to 3500 metres. Cloud developing on Thursday morning with light southwest winds and freezing levels climbing to 3000 metres during the day. Cloudy with convective showers and snow flurries on Friday and the freezing level at 2500 metres.
Avalanche Summary
We have a MIN report of a close call with a size 2.5 wet slab avalanche on a northeast aspect in the alpine on Hour Peak on the McBride range traverse. A skier triggered the large avalanche that released down 30 cm on an old melt-freeze crust and propagated a fracture about 50 metres wide. Most commercial operations in the region have finished their season and data is becoming sparse.
Snowpack Summary
Cornices remain a concern, in part because of the potential to trigger wet slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important. 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. With the warmest weather this year forecast, layers in the mid snowpack and near the ground have the potential to wake up and become active. While isolated and unlikely, avalanches could be very large. 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.
