Regions
Banff Yoho Kootenay.
New snow on Sunday night has created some soft slabs. These are mostly soft and predictable, but watch out for local wind effect and deeper storm snow amounts. Ice climbers should be wary of sluffing in steep terrain!
Weather Forecast
5-10 cm is forecast to fall Tuesday afternoon, and then temperatures will drop with clearing skies on Wed and Thursday and lows into the -20's. Expect to see the winds switch from MW to SE on Tuesday morning and increase to moderate SE in the alpine.
Snowpack Summary
10-30 cm of soft storm snow now covers a mix of sun crust, facets, wind slab and surface hoar depending on the aspect and elevation. We are calling this layer the Dec. 15th layer, and it will become reactive as we get more load on it. The lower snowpack is generally facetted with no shears present.
Avalanche Summary
Several small size 1-1.5 natural and skiier controlled avalanches involving last nights storm snow were observed mostly in the Lake Louise Ski Hill area and backcountry. Additionally, there were a few isolated small avalanches around Sunshine and Bow Summit areas where they received less snow.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.