Avalanche Forecast

On Saturday, an observer near Holden reported about 8 inches of total snow accumulation since the 3rd with loose avalanches in the surface snow and small drifts at upper elevations. Sunday will bring continued cool temperatures and a chance for light snow near the Cascade Crest. Expect some clearing over the Wenatchee Mountains and the far eastern slopes of the Cascades. Closer to the Cascade Crest skies will be mostly cloudy. You may see some small loose wet avalanches on sunny slopes in the eastern part of the zone. In the northwest corner of the zone, near Holden, you may be able to trigger lingering small wind slabs above treeline.

Unreactive small drifts, formed Tuesday night into Wednesday, can still be found near and above treeline but avalanches will be hard to trigger. Large cornices loom on most high ridges from many westerly wind events this winter. Use caution to not travel on or under overhung cornices.

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, like in this profile from Dirtyface on March 3rd. Take the time to assess for the snowpack if venturing to higher elevations or more remote and committing terrain.

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