Very dangerous avalanche conditions will develop with the ongoing storm.
Avoid avalanche terrain during periods of heavy snowfalls.
Forecasted snow amounts will likely develop reactive storm slabs, especially on leeward terrain features where deposits are deep. Large natural avalanches are likely, particularly when moist and heavy snow will overload the underlying dry snow. Be aware that slab avalanches could step down to a crust layer and produce larger-than-expected avalanches.
A large storm slab avalanche was triggered by a skier on Metal Dome on Tuesday on an open east-facing slope at treeline. Another skier-accidental avalanche was reported to have failed within the storm snow near Oboe on a northwest slope. A natural avalanche cycle is expected with this upcoming storm.
Up to 35 cm of new snow has fallen into the region since Monday. Ongoing southerly and previous northerly winds have affected the storm snow in any open terrain and near ridgelines. On sheltered slopes, up to 70 cm of powder storm snow can be found. Snow is heavy and moist at lower elevations.
A thick widespread crust formed in late December is down 50 to 80 cm. In the alpine, it is thin and breakable. Professionals are concerned that small avalanches may run down to this crust and create larger-than-expected avalanches.
Near the base of the snowpack, a weak facet/crust layer from mid-November can be found and remains a concern for triggering with large loads or on thin spots. In general, the snowpack is weak, faceted, and shallow.
A strong storm will affect the region early Thursday. Moderate to heavy snowfalls are expected before the subtropical flow pushes warm air and rain onto the region until Saturday.
Wednesday night
Cloudy, snow 5-10 cm, moderate southerly winds increasing to 60 km/h, freezing levels around 1200 m, low of -4C at treeline.
Thursday
Stormy 25-45 cm of snow, rain at lower elevation, moderate southerly winds gusting 60 km/h, freezing levels around 1200 m rising to 2000 m, high of -1C at treeline. 30-50 mm wet snow/rain overnight.
Friday
Stormy 15-25 cm of wet snow, rain at lower elevation, moderate southerly winds gusting 60 km/h, freezing levels around 2000 m, high of +2C at treeline.
Saturday
Cloudy, lingering flurries, moderate southwesterly winds gusting 40 km/h, freezing levels dropping to 1500 m, high of -3C at treeline.
More details can be found in the Mountain Weather Forecast.
