Regions
Northwest Inland.
Watch for wind slabs lurking in unusual places as the winds have been shifting direction.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Cold and dry with strong N-E outflow winds. A temperature inversion may form on Wednesday.
Avalanche Summary
A naturally-triggered size 2 slab was observed on Saturday on an alpine NE aspect in steep, windloaded terrain. A naturally-triggered size 1.5 wind slab was also observed at treeline on a north aspect in the Hankin area, which probably failed on Wednesday or Thursday. On Tuesday we received a report of a size 1.5 skier remotely triggered avalanche in the far north of the region. It released on a steep, wind loaded feature and was triggered from 5m away. The 25-45 cm thick slab occurred around 1600 m elevation.
Snowpack Summary
10-20 cm new snow from Friday night is likely to form new wind slabs on south to west-facing slopes as winds shift into an outflow pattern. Older wind slabs from previous westerly winds are buried underneath. A layer of buried surface hoar down about 30-50 cm appears to be spotty in distribution, but may still be a concern in some areas. Near the base of the snowpack, the mid-November crust-facet layer has become less likely to trigger, but is still in the back of our minds.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.