Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
April 12, 2023
Submitted:
April 12, 2023
Observer:
NWAC Forecaster - Dallas Glass
Zone or Region:
Snoqualmie Pass
Location:
Commonwealth Basin/Cave Ridge (All Aspects Near and Below Treeline (3000-5300ft))

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
None Experienced

Media/Attachments

The snowpack can be divided into new snow, wet snow, and old dry snow.
New rollerballs started with just a little sunshine. These are often the precursor to Loose Wet avalanches.
Textured surfaces and scoured slopes indicate wind slabs could be near by.
This small wind-loaded pocket cracked easily.
There were lots of natural avalanches during this last atmospheric river (4/8-4/11).
Several large debris piles along the west face of Kendall Peak. W, approx 5200ft. WS-N-D3-R2-U
Debris piles on Kendall Peak. SW 5400ft
A small natural loose avalanche in a very high traffic area. NW, 3800ft, L-N-D1-R1-S
A large natural avalanche on Red Mt. SSE, 4700ft, WS-N-D2.5-R2-U
Open creeks are still an issue around the Pass. Look for solid safe crossings.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Wind:
Light , N
New/Recent Snowfall:
New snow a bout 4-6in above 5000ft. About 1-2in at Pass level.

It was a really nice morning out around Commonwealth Basin! Thin clouds and a bit of filtered sunshine, gave way to significant sun breaks. While air temps felt very cold, the sunshine made it feel more spring-like. Winds were barely noticeable.

Today: A few very small loose wet avalanches were seen that occurred during the morning. They were on various aspects, generally below treeline. They were frequently associated with rocky areas, or very steep (~50 degrees) trees.
Old: It looked like the mountains went through a few different avalanche cycles during the past weekend's storm. The earlier cycle seemed to include some larger wet slab avalanches in the D2-3 size. The later cycle may have included a few wet slabs, but also included more extensive Loose Wet avalanches D1.5-2.

Snowpack Observations

New Snow: The new snow totals increased rapidly above about 5000ft. 1-2 inches at Pass level became around 6 inches up higher. The new snow was very light dry and cold. Not surprisingly this resulted in a poor bond to the newly forming crust. However, there wasn't any slab properties away from wind affected areas. This resulted in a few small sluffs, but nothing that entrained much snow or ran very far. As the sun hit E-S aspects during the morning, the new snow became much heavier and wetter, ultimately producing small rollerballs and a few natural loose wet avalanches.
Wind: In the near treeline band, the wind had formed textured surfaces, drifts, and even scoured slopes. Even with all the signs of wind transport, wind slabs were hard to find. I was able to get a few small wind-loaded pockets and test slopes to crack, but they only produced very small slabs.

Wet Snow: Below the new snow, a crust is starting to form. It was most supportable at lower elevations and in the trees, where less new snow allowed the wet snow to more easily freeze. Even still the crust was not generally boot-supportable anywhere. Around, 5000ft, I repeatedly sank up to my knee.
The wet snow layer was typically about 12-18inches thick and consisted of large grain melt-forms.

Below the main wetting front, the snowpack remained dry and layered.

Glide: Plenty of glide cracks were seen around the valley, but I did not see any fresh glide avalanches.

Creeks and holes around rocks remain a hazard. We used extra caution when navigating creek crossing and while traveling near boulder fields.

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