Avalanche Forecast

A frontal system will bring significant snowfall to the west slopes of the Cascades on Tuesday along with increasing winds and a warming trend forecast for late in the day and extending into Tuesday night.  The avalanche danger will quickly increase Tuesday, with very dangerous avalanche conditions developing in the afternoon and worsening overnight. Backcountry travel in avalanche terrain should be avoided Tuesday. 

Fresh storm slabs may entrain recent snowfall, quickly becoming larger and more dangerous than you expect. 

Older wind slabs may lurk beneath the most recent lower density snow. New or recent wind slabs may also produce large avalanches, entraining significant amounts of loose dry snow.

Snow immersion and tree-well hazards continue to increase and pose significant danger. Maintain constant communication with your travel partners.

The active weather pattern seen over the last week will continue on Tuesday. Around 2 feet of snow now sits above the most recent melt-freeze crust in the central and southwest zones. The most recent storm cycle wrapped up Sunday night with cooler temperatures, light to moderate westerly winds and snow showers adding an additional 2-6 inches Monday. 

Moderate to strong winds transported snow forming wind slabs on a variety of aspects at Snoqualmie Pass and the southwest zone including Crystal, Paradise and White Pass Sunday. Less wind transport occurred in the Stevens Pass area Sunday.  

Observations

Central

An avalanche professional in the Stevens Pass area Sunday reported 18 inches of generally right-side-up snow well bonded to the 1/16 crust. No avalanches were observed. 

An avalanche professional in the Snoqualmie Pass area Sunday reported 12 inches of snow well bonded to the 1/16 crust. They observed wind transportation of snow above 4000 feet. Several natural, small and isolated wind slab avalanches were seen in very steep northerly terrain. 

A public observation from the Snow Lake Divide area of Snoqualmie Pass reported a skier triggered wind slab avalanche that broke above the skier and was 12-18" deep. 

South

Professionals in the Crystal area Monday reported 1 to nearly 2 ft of snow above the 1/16 crust in wind sheltered terrain generally well bonded. In areas stripped of snow during Sunday's storm, less than 8" sits above the most recent crust and is poorly bonded. Loose dry avalanches were the biggest avalanche problem encountered Monday, found in steep terrain at higher elevations and easily ski triggered with the potential to run long distances.