Avalanche Forecast

On Thursday, another calm weather day of partly cloudy skies, cold temperatures, light winds, and minimal new snow should allow for generally safe travel conditions around the West-South zone. Even so, you could find isolated pockets of unstable snow in two primary circumstances.

• Wind drifted pockets on shaded slopes higher in the terrain. 

• Steep sunny slopes where the surface becomes wet and sticky during periods of prolonged sunshine. 

Take time to carefully evaluate steep lines for evidence of wind and sun affected snow before committing to the slope. 

Over the past week, a very aspect dependent snowpack developed around the region. Shaded slopes continue to hold a soft dry and layered snowpack. Recent strong winds on Tuesday may have redistributed some of the snow on these slopes creating deeper pockets and scoured surfaces. On sunny aspects, a firm melt-freeze surface formed in many areas. In these locations, you could experience icy conditions, particularly early in the morning.

March 5, 2020 (The regional synopsis is updated every Thursday @ 6 pm)

Ridgetop wind transport near Washington Pass. 3/4/20 Photo: Josh Hirshberg

The beginning of March brought the first spring-like weather to the region. The days are getting longer and the sun (when it shines) has a noticeable effect on the snow. Alternating sun breaks and snowstorms is the theme of the week and the avalanche danger fluctuated just as fast as the weather. The southern zones and the east slopes have seen periods of light snowfall and significant sunshine while the northern zones and west slopes have had significant snowfall and occasional sun breaks. Above freezing temperatures were common at lower elevations throughout the region. 

Last week in review:  Temperatures were above freezing at most trailhead locations and concerns about the previous week’s buried surface hoar and weak layers were fading. Saturday temperatures plummeted as strong winds and new snow built wind slabs in most areas and drove the avalanche danger to considerable in almost every zone. Sunday’s calm weather and clearing in most areas helped stabilize wind slabs, but our attention turned to the strength of the sun and daytime warming. Lingering wind slabs and loose wet avalanches were forecast in every zone. For the remainder of the week, the avalanche problems in every zone were confined to the recent snow and each brief storm cycle had us thinking about wind slabs at upper elevations and loose wet avalanches from daytime warming and sunshine.

Spring isn’t actually here -- another round of cold temps and snow showers are on the way this weekend, but this past week’s oscillating weather is a good reminder to begin to shift our mindset. The sun is gaining strength, the days are getting longer, and we begin daylight savings this week. Even a brief period of sunshine can dramatically alter fresh, new snow. Check the mountain weather and avalanche forecasts for the most up to date info, enjoy the backcountry and let us know what you see out there!

--Peter Moore

Wet loose avalanche debris near Snow Lake. 3/5/20 Photo: Dallas Glass

Fresh cornice development from strong winds in the Stevens Pass backcountry. 3/4/20 Photo: Tom Whipple