Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain on Thursday

THURSDAY: Periods of snow, accumulation 15-35cm with the greater amounts in the southernmost portions of the region / Moderate to strong southwest winds / Alpine temperature -2 with a freezing level of 1500mFRIDAY: Cloudy with isolated flurries / Moderate to strong west wind / Alpine temperature -4 with a freezing level of 1200mSATURDAY: Cloudy with sunny periods / Moderate west wind / Alpine temperature -9More details can be found on the Mountain Weather Forecast.

With additional snow, warming temperatures and wind on Thursday expect to see another spike in avalanche activity as the load grows over weak layers deeper in the snowpack. Storm slab avalanches have the potential to step down to the basal weakness which would drastically increase the size and destructive potential of a resulting avalanche. On Monday, numerous skier triggered storm slab avalanches size 1-1.5 were reported. Explosives also triggered storm slabs up to size 2.5. These slabs were typically around 30 cm thick. One of these storm slab avalanches stepped down to the basal weakness resulting in a slab that was up to 150 cm thick. On Monday in the Lizard region, natural avalanches up to size 2.5 were observed.

Another 20-30cm of new snow is expected through the day Thursday to add to 90 cm of new low density storm snow that accumulated last weekend. Strong shifting winds have redistributed the previous storm's snow in exposed terrain forming touchy wind slabs. These wind slabs are now obscured by the latest blanket of snow. All this overlies a highly variable old surface which may include wind affected surfaces, facets, and/or a rain crust below around 1500 m. Recent reports suggest a poor bond between the storms' snow and the old surface. In deeper areas, the snowpack appears to be well settled with isolated concerns about the mid-December facet layer which was buried 50-100 cm deep prior to the weekend storm. In shallow snowpack areas and at lower elevations, the snowpack is weak, faceted, and has no structure. Prior to the storm, it was possible to step onto the snow surface in these areas and sink right to the ground.