Tricky conditions persist in the alpine with fresh wind slabs and the continuing possibility of avalanches releasing on deep weak layers. Conservative terrain selection remains highly recommended.
Summary
Confidence
Moderate -
Weather Forecast
On Friday, 10-15 cm of new snow is expected with moderate to strong alpine wind from the southwest and freezing levels reaching around 1500 m in the afternoon. Another 5-10 cm is expected on Saturday with moderate alpine wind from the southwest and freezing levels around 1500 m in the afternoon. Mainly dry and sunny conditions are forecast for Sunday with light alpine wind and afternoon freezing levels reaching upwards of 1800 m.
Avalanche Summary
On Wednesday, a natural size 2 slab was observed on a south aspect at 1800 m which was 100 cm thick. Natural sluffing up to size 2 was reported as well as two natural cornice failures. One of these triggered a size 3 slab which released down 200 cm. Ski cutting trigger two size 1.5 wind slabs which were 30-40 cm thick. On Tuesday, a natural cornice release triggered a size 1.5 storm slab on a northwest aspect at 2050 m elevation. On Monday, a natural cornice release triggered a size 3.5 deep persistent slab on a north aspect at 2500 m released on glacier ice and ran to valley bottom. Over the weekend, a widespread avalanche cycle occurred with avalanches up to size 4.5. This included very large cornice releases, avalanches releasing on layers near the base of the snowpack, propagations over 1 km wide, and mature timber being broken.
Click here for photos of the recent avalanches.On Friday, wind slabs and cornice are expected to be reactive at higher elevations. We are in a low probability, high consequence scenario for persistent slab avalanches failing on buried weak layers.
Click here for more details.Snowpack Summary
15-25 cm of new snow typically overlies the thick rain crust which formed over the weekend. The crust has been reported as high as 2000 m and has been reported to be supportive to skiers between 1500 and 1900 m. Alpine wind has recently been strong from a variety of directions and has formed wind slabs on all aspects. Large cornices are also reported on northerly aspects in the alpine. The rain crust which formed last week is now down 50-60 cm and generally seems to be well bonded to the surrounding snow. The February weak layers are down 100-150 cm and woke up during the recent storm cycle with many avalanches stepping down. 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
