Tricky conditions are expected to persist at higher elevations with new snow and wind building slabs as well as the continuing possibility of avalanches releasing on deep weak layers. Conservative terrain selection remains highly recommended.
Summary
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Saturday
Weather Forecast
4-8 cm of snowfall is expected Friday overnight with moderate to strong southwest wind in the alpine and freezing levels around 1200 m. Another 3-6 cm is expected on Saturday with sunny breaks in the afternoon. Alpine wind is forecast to be moderate from the southwest and freezing levels are expected to reach around 1600 m. On Sunday, a mix of sun and cloud is expected with light alpine wind and freezing levels reaching around 1700 m. Mainly cloudy conditions are forecast for Monday with light snow flurries.
Avalanche Summary
On Thursday, a natural size 3 avalanche was reported on a northeast aspect at 2500 m and a size 1.5 cornice failed on a north aspect at 2600 m. Solar triggered loose avalanches up to size 2 were also observed. Skiers were triggering size 1 wind slabs in the alpine and explosives triggered three avalanches, one of which failed on the ground down 100 cm. On Wednesday, a natural size 4 deep persistent slab was reported but the date of the avalanche is uncertain. This failed on a broad ridge feature on south through north aspects, was 200 cm thick, and 1000 m wide. A natural size 2.5 storm slab was also observed on a northeast aspect at 2400 m and a natural cornice failed on west aspect at 2300 m which was solar triggered. On Saturday, wind slabs are expected to be touchy at higher elevations. Cornices are large and may become weak with daytime warming or during stormy periods. We are in a low probability, high consequence scenario for persistent slab avalanches failing on buried weak layers.
Click here for more details. Click here for photos of the recent large avalanche cycle.Snowpack Summary
10-15 cm of new snow overlies a widespread crust below around 2100 m and higher on solar aspects. Alpine wind has recently been strong mainly from south through west aspects and has loaded leeward slopes in exposed terrain at treeline and in the alpine. Large cornices are also reported in the alpine and appear to be largest on northerly aspects. At lower elevations, there are a couple rain crusts in the upper snowpack. The February crust/facet layer is now down around 90-150 cm and has been reactive with several avalanches recently releasing on it. It is expected to be most reactive in the alpine where the snowpack remains dry. The deep mid-December facet layer and November rain crust both still linger near the bottom of the snowpack and a few avalanches and cornice falls have stepped down to these layers recently resulting in very large avalanches.
rbuhler,
Avalanche Canada
