Tricky conditions are expected and conservative route selection is critical.
Weather Forecast
Thursday: An additional 5-15cm of snow with freezing levels in valley bottoms and light to moderate westerly winds. Friday: A mix of sun and cloud, but dry, with freezing levels in valley bottoms and moderate southwesterly winds. Saturday: Increasing cloud with light snow starting in the afternoon. Freezing levels remaining in valley bottoms and light easterly becoming moderate southerly winds.
Avalanche Summary
On Tuesday, sled testing in Smith Basin north of Elkford produced whumpfing and shooting cracks on a slope adjacent to a recent sled triggered small wind slab avalanche.
Snowpack Summary
As of Wednesday morning, 5-10 cm of fresh snow adds to the previous storm snow that is bonding poorly to the old snow surface buried early January. East of Crownest Pass this old snow surface was widely wind affected. Extensive scouring has been reported in some areas and and stiff wind slabs exist in lee features at treeline and in the alpine. In areas that have seen less extreme wind, recently formed wind slabs are likely softer, deeper, and may overlie surface hoar, facets, and/or a sun crust which formed at the start of January. In either case, snow pit tests in wind loaded features show recently developed slabs are failing under moderate loads and can propagate over wide distances. The early December crust can be found down around 60-90cm. It is not currently expected to pose an avalanche problem but could wake-up in the future with substantial warming or heavy snow loading.
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.