Northwest Avalanche Center - Public Observation

Name:

Enji Cooper

Observation Date:

February 18, 2022

Submitted:

February 18, 2022

Zone or Region:

Snoqualmie Pass

Activity:

XC Skiing/Snowshoeing

Location:

Snow Lake (Snoqualmie)/Avalanche Mountain Environs

Did you observe any avalanches?

Yes

Comments:

There was a lot of mini wet loose slides near sun-exposed boulders and trees (suspected trigger: tree bombs) in the Snow Lake basin on N facing aspects (S side of the basin), as well as a variety of other areas. The slides were small (for the most part), but there were some larger ones that had fallen over the past week and today.
Snow Lake Divide had some larger wet loose slides (D1~D1.5) which had been triggered over the course of the day.

None reported

As suggested previously... there was a lot of wet loose activity.
I started mid-morning from Alpental (8:15) and booted up to Source Lake using the cat track, then old snowshoe and skin tracks. The cat track was slick until the cat groomed up the track (then it was just large fractured crystals). This was consistent with conditions on the return.
Stepping off the old snowshoe/skin tracks under the trees had minimal boot pen (maybe 0.5" tops). Once I got out of the trees though the boot pen increased to about 1". It was still pretty solid in the morning though, so I wasn't terribly concerned about risk.
I walked the ridge (from Snow Lake overlook) using the winter route using snowshoes, then traversed over to the Avalanche Mt saddle. I crossed a lot of undisturbed avalanche slopes in the morning. I felt slightly alarmed, but not greatly; I did my best to not linger on open slopes or slopes over 35°.
When I got back to the saddle area though, things were getting a bit more interesting since the sunlight was hitting the trees, causing the snow to melt and snow bombs to drop. The snow conditions in the shade were nice, storm-snow like conditions, but the snow conditions in the sunlight were sloppy wet loose. There wasn't cohesion between the surface layer and the next layer down--a weak wet-ish slab about 1/32" thick (it broke easily when I tried to pick it up). All of the snow underneath resembled Cascade Concrete. I engaged the snowshoe crampons by stomping to mitigate sliding downhill since the slope was 30°+, and leveraged rain shadows next to trees/shaded snow.
The snow along the Avalanche Mt ridge was low coverage: <6" in areas with lots of exposed rocks and heather. Some of the snow had strength, but other portions didn't (I suspect the rocks underneath provided support). I used a combination of snow and rocks to get up to and down from the summit. On the way down I switched from booting to my steel crampons. It was difficult to purchase the base snow given that I hadn't punctured the top layers significantly on the way up, but crampons were definitely the right tool for the job. After I got back to the bottom of the basin, I switched back to snowshoes since I was sinking in over 2", and used a slightly more conservative route where I felt necessary, i.e., I gave the uphill slope buffer and was careful around drainages (looked at snow bridges before crossing, etc). I had one spot where I lost my footing snowshoeing downhill, slid 10', and had to self-arrest. I wasn't physically hurt, but was definitely caught off-guard by the surface layer. After I got to the top of the Snow Lake saddle (near Snow Lake Divide), I took off the snowshoes and booted it to the bottom of the basin. The area was shaded, so the postholing was reasonably minimal (2"~3"). The boot skiing was good where I could get it . Some of the drainages around Source Lake and the upper Snow Lake pond were open and running with obvious older glide cracks.