Avalanche Forecast

New and shallow storm and wind slab should begin building Wednesday afternoon and evening as a Pacific frontal system approaches from the west. 

New snow may initially bond poorly to a variety of snow surfaces Wednesday with a thin sun crust on solar aspects and low density snow and/or surface hoar on shaded and non-wind affected terrain.  

Change your travel plans if storm hazards deteriorate more quickly than forecast. 

Additional snowfall and wind loading Wednesday night will increase the storm related avalanche hazard on Thursday. 

Weather and Snowpack

Two fair weather periods earlier this month allowed surface hoar and near surface faceting to occur. These persistent weak layers were buried intact on January 3rd and 11th throughout the Cascades. Two heavy rain events, one about January 21st and another January 27-28th have eliminated the January persistent weak layers and formed crusts in the upper snowpack along the west slope zones.

A strong occluded front with strong winds crossed the Northwest on Friday. NWAC stations along the west slopes had about 1-1.5 feet of new snow by Saturday morning. Light amounts of snow followed at the tail end of the storm by Sunday morning. The most recent snowfall fell on top of the rain crust from late last week. Cool and benign weather followed Sunday through Tuesday. Varying amounts of sunshine Tuesday along the west slopes likely formed a sun crust on steeper solar aspects. 

Recent Observations

Three NWAC pro-observers visited the Stevens Pass and Paradise areas on Sunday and generally reported possible wind slab on previous lee slopes and possible storm slab in storm snow in the near and above treeline as the main avalanche problems.

NWAC pro-observer Lee Lazzara was in the Mt Baker area on Monday and reported small wind slab varying in depth from 20-40 cm over slightly lower density snow but lacking clean shears. Skiers were also triggering loose dry avalanches on steep 45 degree slopes.  Lee reported similar conditions in the Baker backcountry on Tuesday with the rain crust 50-80 cm down. 

Pro-observers Ian and Dallas were on Snoqualmie Mt Tuesday and generally found low density snowfall above the most recent rain crust providing good skiing conditions with minimal wind effects. The most recent snowfall was not cohesive enough to form a storm slab in their specific area. 

NWAC observer Jeff Ward was in the Stevens Pass area Tuesday. He generally found a stable upper snowpack, but observed new surface hoar growth most prominent in Highland Bowl near ridgecrest.