Avalanche Forecast

With several inches of new snow possible through Sunday morning, small loose avalanches are the name of the game.

You can kick off these point release avalanches on very steep slopes. They are only dangerous where they can knock you off balance above terrain traps. If the sun stays behind the clouds most of the day, you are most likely to find loose dry avalanches. If the sun comes out for an extended time, loose wet avalanches will become more likely on very steep solar slopes. Pay attention to changing surface conditions and avoid similar steep slopes if you see small natural avalanches. Generally safe avalanche conditions expected otherwise. 

Two skier triggered avalanches were reported Friday. One was a small loose wet avalanche skier triggered on a S-SW aspect that posed a hazard as it carried downslope into a stand of trees.

Exercise normal caution around cornices. Cornice lines are still large in some areas. Give them a wide berth when traveling along ridgelines and don't linger below slopes with large cornices. 

On Sunday, you may be able to trigger a similar small loose wet avalanche on solar aspects if the sun pokes ou for an extended period of time. Photo: Sam Siemens-Luthy 3-6-20 

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