Avalanche Forecast

Wednesday will bring slight cooling, light snow and gusty winds after Tuesday’s warming. Northerly aspects are likely to continue to harbor cold dry snow. Loose dry snow may be transported by the wind forming wind slabs on lee slopes at upper elevations. Where enough sun shines on Wednesday, you may encounter small loose wet avalanches on steep sunny slopes. They are only dangerous where they can knock you off balance above terrain traps. 

In the adjacent East Central zone, a rain event in early February formed a prominent crust that you can still find near the surface sometimes with an adjacent layer of faceted snow. There are also a couple of layers of buried surface hoar or near-surface facets in the upper 3 ft of the snowpack. It's been a while since any avalanches were reported on these layers but you may still be able to find them. With far less data in this zone, take the time to assess the snowpack if venturing to higher elevations or more remote and committing terrain.

Forecast Schedule and No Rating definition

We do not have enough specific snowpack information to issue an avalanche hazard rating for the East South zone. However, even when No Rating is applied, applicable avalanche conditions and backcountry travel advice will be provided throughout the season - this forecast is updated every day, all winter long!  When weather systems produce very dangerous avalanche conditions in adjacent zones, NWAC will issue an avalanche warning for this zone as well.

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