Regions
Northwest Inland.
Be on the lookout for pockets of wind slab below alpine ridges. Sunny skies can make these slabs increasingly sensitive, even on cold days.
Confidence
Moderate - Due to the number of field observations
Weather Forecast
Friday: Mostly sunny / Strong to moderate easterly winds diminishing in the afternoon / Weak inversion with a alpine high of -16 C.Saturday: Mix of Sun and cloud / Light to moderate easterly winds / Alpine high of -18 C.Sunday: Sunny / Light easterly winds / Alpine high of -16 C.
Avalanche Summary
Wind slabs avalanches are a concern where wind is being blown around. No new avalanche reports on Wednesday; however, check out the recent MIN report for the Miller Ck/ Crater Lk area. That report indicated a natural size 2 slab avalanche which appeared to be a cornice failure in steep complex terrain. The avalanche was noted from a southeast aspect at 1850 m.
Snowpack Summary
Recent winds have blown from many directions, most recently from the east. As a result, expect wind slabs to exist on a wide variety of exposed slopes. A layer of surface hoar was reported around Hudson Bay Mountain last week, which now sits beneath 40-50 cm of settling snow. A thick rain crust that formed in early November is now buried 50-60 cm deep, and recent snowpack tests produced sudden results on facets (sugary snow) above this crust. Early season snowpack observations are still very limited in the region, but reports suggest the average snowpack depth is 50-90 cm at treeline and 120 cm or greater in the alpine.
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.