Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain

Tuesday: Unsettled conditions and convective air could bring 5-10 cm of new snow with mostly cloudy skies. Ridgetop winds will be moderate from the SW and freezing levels near 1700 m. Wednesday: Snow amounts 10-20 cm. Ridgetop winds light-moderate from the South and freezing levels near 1700 m.Thursday: Cloudy with possible sunny breaks. Ridgetop winds light from the SW and freezing levels near 1500m.

On Sunday, large natural and explosive controlled slab avalanches were observed. A natural cornice fall produced a size 3.5 avalanche from a SE aspect and control work continues to produce several size 3 and a size 4 avalanche that ran to ground from a NW aspect. On Tuesday, the recent storm snow is expected to be reactive at higher elevations, especially in wind loaded terrain and on steep convex features. Cornices are large and may become weak with daytime warming or during stormy periods and have proven to still trigger very large avalanches from the slopes below. We are in a low probability, high consequence scenario for persistent slab avalanches failing on deep buried weak layers. Click here for more details. Click here for the Forecasters' Blog.

20-40 cm of snow has now accumulated over the past week which overlies a widespread crust below around 2100 m and higher on solar aspects. On steep solar aspects, a new sun crust is also being reported. Alpine wind has recently been strong mainly from south through west aspects and has loaded leeward slopes in exposed terrain at treeline and in the alpine. Large cornices are also reported in the alpine. At lower elevations, there may be multiple crust layers in the upper snowpack which are now generally well bonded and stable. At higher elevations, the February crust/facet layer is now down around 90-150 cm and has been reactive with several avalanches recently releasing on it. It is expected to be most reactive in the alpine where the snowpack remains dry. The deep mid-December facet layer and November rain crust both still linger near the bottom of the snowpack and a few avalanches and cornice falls have stepped down to these layers recently resulting in very large avalanches. Heavy triggers like cornices and explosives continue to sporadically trigger deep weaknesses in the snowpack as recently as Saturday.