Unstable snowpack tests from Blue Lakes to Indian Valley

Poor visibility prevented us from approaching the site of the recent avalanche on The Nipple for a crown profile. Instead, we went to safe terrain near Tamarack Junction and in Indian Valley for test profiles.

At 8300ft on a north facing opening in the trees near Tamarack Junction, we found a layer of small facets buried on Dec 25th, and a Compression Test produced Sudden Planar results on it, but an ECT did not propagate. It likely did not have enough slab on top of it. We also found the Dec 11th facets here, which were large and weak. The ECT did not trigger this layer at all, so I tried a Deep Tap test which had an obvious Sudden Collapse result.

At 8000ft on an east facing opening in the trees in Indian Valley (pindrop), we performed two test profiles with similar results (SnowPilot graph). Compression Tests and an ECT indicated propagation was likely on the Dec 11th facets. The facets buried on Dec 25th were also present here.

Pic 1: Near Tamarack Junction, the Dec 17th and Dec 25th layers are clearly visible as the thin stripes. The Dec 11th facets are the rough layer near the bottom. It was difficult to excavate cleanly, because the facets fell from the profile wall. My saw is just under 90cm (3ft).

Pic 2: Signs of settlement around Tamarack Junction, which unfotunately in our current snowpack means the slab is probably gaining strength while the facets below may not be. This is supported by an ECT which did not trigger the Dec 11th facets, but a Deep Tap that indicated likely propagation.

Snowpit: Very similar to what we saw at Tamarack Junction, and two snowpits on the same slope with similar results.