You could trigger slab avalanches above treeline and wet avalanches on steep sunny slopes. If you see signs of instability like shooting cracks and recent avalanches, stay off of slopes steeper than 35 degrees. A storm will increase avalanche danger on Sunday.
Warming temperatures and sun will trigger more loose wet avalanches on steep, sun-exposed slopes. Look for signs of loose wet activity such as rollerballs and other small fan-shaped avalanches as temperatures warm. You may even be able to trigger avalanches on steep slopes in the shade.
(3/24/2021) An example of small loose avalanches near Washington Pass. Photo: Josh Hirshberg
Around 1ft of snow fell on Wednesday with moderate wind drifting at upper elevations. While wind slabs are becoming less likely, you may still be able to trigger avalanches on leeward slopes above treeline. Look for softer, weak layers at the interface of Wednesday's storm snow which could make the snow slide easily. Avoid unsupported, wind-loaded slopes. You can use hand shears, quick tests, and small test slopes to check how well new snow is bonding.
Example small slab avalanche on Tye Peak on March 22nd.
On Wednesday and Thursday, observers reported that slab avalanches in the new snow were reactive and failed about around 8" deep on a recently buried melt-freeze crust. The wind was strong enough to drift the newly fallen snow into thicker slabs near ridgetops and on exposed features. On Thursday, observers on Jim Hill and Arrowhead reported natural and triggered wet loose avalanches.
Generally, cornices aren't as large near Stevens Pass as you may find further north in the Cascades. Continue to give cornices plenty of room when traveling on ridges and stay out from under them. Several large glide cracks and a few glide avalanches were observed recently. If you notice crevasse-like cracks in the snowpack, avoid areas below the cracks.
Deep persistent slab avalanches were a concern into early March, but now they are dormant and unlikely. The layer of facets on a crust from Mid-January was responsible for the February avalanche cycles is now buried 8-9 feet deep. The last known deep slab avalanche in this zone was on March 1. Major warming events later in spring and summer could trigger further rounds of avalanches on this layer.
During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.
