Wind slabs at upper elevations may be reactive to human triggers, especially on leeward slopes or behind terrain features. Avoid solar slopes if the sun comes out.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Thursday
Weather Forecast
Wednesday: Mix of sun and cloud. Alpine high near plus 3 and freezing levels rising to 1900m. Ridgetop winds light from the South. Snow expected overnight 10-20 cm. Thursday: Periods of snow 10-20 cm with heavier amounts expected later in the day above 1300 m. Alpine high near plus 2. Ridgetop winds strong from the East. Friday: Cloudy with possible sunny breaks. Alpine temperatures near -1. Light-moderate precipitation amounts. Ridgetop winds moderate to gusty from the southwest.
Avalanche Summary
On Monday we received reports of several natural size 1.5 dry loose avalanches, and confined to the recent storm snow. No new avalanche reports submitted on Tuesday.
Snowpack Summary
Up to 12 cm of new snow fell on Monday. This new may have a poor bond to a wide variety of old snow surfaces including a melt-freeze crust on sunny aspects, or surface hoar (up to 30mm in size) and/or dry snow on north aspects above 1500-1800m.Deeper in the snowpack, the mid-December and late-November weak layers are composed of crusts and sugary facets, which are down 150-300 cm. These layers have been dormant but may be awoken by a large trigger, such as a cornice fall, or by humans traveling in thin-to-thick snowpack areas.
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.