Avalanche Forecast

Issued: Mar 7th, 2020 10:00AM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low.

Northwest Avalanche Center NWAC, Northwest Avalanche Center

Generally safe avalanche conditions are expected Sunday. Be mindful of small loose wet avalanches on very steep solar aspects if the sun comes out for an extended period of time. Move quickly below slopes with large overhanging cornices and give them space along ridgelines.

Summary

Discussion

With up to 4” of new snow expected through Sunday morning, small loose wet avalanches are possible on very steep solar slopes. Loose wet avalanches are easy to anticipate and avoid. Pay attention to changes in the surface snow if the sun comes out for an extended time, watch for small natural point releases or sluffs as an indicator of increasing hazard, and consider the consequences of a small avalanche above around terrain traps like cliff bands, exposed rocks, or steep trees. 

Exercise normal caution around cornices. Give them a wide berth when traveling along ridgelines and don't linger below slopes with large cornices. 

In areas that don’t receive new snow, expect potentially difficult travel conditions due to variable snow surfaces. You may encounter refrozen wet avalanche debris from earlier this week, breakable crusts, and even bare ice in wind scoured spots above treeline. Don't cross steep icy slopes if you are not confident you can safely self-arrest a fall. 

Snowpack Discussion

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

Valid until: Mar 8th, 2020 11:00AM