Avalanche Forecast

Issued: Mar 9th, 2020 11:00AM

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

Northwest Avalanche Center NWAC, Northwest Avalanche Center

Avalanche conditions remain generally safe. As the sun heats the surface snow, very shallow loose wet avalanches are possible. Travel conditions remain the largest concern with breakable crusts in some areas below treeline and a dangerous blue ice crust lingering on N and some E aspects.

Summary

Discussion

On Monday, the sun combined with slightly milder temperatures to soften the snow near and below treeline at Mt. Hood Meadows, with many slopes in this elevation range undergoing a melt-freeze cycle. Snow surface conditions were variable, with generally an inch of snow that is wind-affected in exposed areas and sits above crusts from late last week. Avalanche conditions were generally safe.

On Tuesday, the situation should be similar, with more sun and milder temperatures (5F warmer) softening slopes above treeline as well. 

While we don't expect avalanches that are generally large enough to harm you, continue to travel with normal precautions. Avoid obviously wind-loaded very steep or extreme terrain features. Very shallow loose wet avalanches will become more likely on very steep solar slopes that receive direct sun as the day wears on. Pay attention to changing surface conditions, watching for wet unconsolidated surface snow and avoiding similar steep slopes when you see small natural avalanches. 

Travel/riding conditions remain variable to challenging with breakable crusts below 5500 ft in the woods and a blue ice layer still exposed on N and some E aspects. On some E aspects, the ice layer will be hidden by a thin veneer or fresh snow but remains very dangerous. Don't cross steep icy slopes if you are not confident you can safely self-arrest a fall.

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

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 10th, 2020 11:00AM