Sea To Sky

Good

Saturday night and Sunday: An upper ridge remains over the coast bringing dry conditions and light NW and N winds and skies with few to scattered cloud cover. Freezing levels should rise to 900 m. in the afternoon and temperatures dropping to -8 at night. Monday: The ridge remains anchored across the South coast but cloud cover will thicken somewhat in the northern part of the region due to a system passing over the Northwest coast. Winds should remain light and temperatures becoming relatively mild in the afternoon. Tuesday: We could see a bit of an inversion with freezing levels reaching 1300 m. in the afternoon and temperatures warming up to 0 C in the alpine. No precipitation is expected, winds remaining light.

A large slab avalanche (size 3) was triggered by a heavy load (winch cat) yesterday in the Whistler area. The slab was triggered in a shallower spot and ran on the Nov. 6 crust/facets layer which was sitting 40 cm above the summer firn. More information about this avalanche can be found here.  Some sluffing (loose dry avalanches) were also observed in steep terrain. Large glide cracks were also observed on SE aspects in the alpine.

20-40 cm of low density snow can still be found at the surface in the alpine and below. Some minor wind effect created wind slabs that are limited to lee and crossloaded terrain in alpine and open treeline terrain. No significant shears were obtained when the top or mid snowpack was tested. However, fragile cornices may exist and a surface hoar interface has been observed near the surface in sheltered areas. Near the base of the snowpack, a crust/facet layer is now unlikely to be triggered. However, professionals are still mindful of thin snowpack trigger areas or large loads (like a large cornice) which could wake it up again, leading to a very large avalanche. Yesterday's size 3 avalanche is a good demonstration of this concern.