Signs of another round of wind slab and storm slab instability on Castle Pk.

We toured the NW side of Castle Peak today and the E side of Andesite Peak taking a look at wind slabs and storm slabs. Evidence of instability associated with both of these avalanche problems was present. We started out the morning in high intensity snowfall of S2-S3 (1+ inch per hour). Snowfall tapered off around midday and cloud cover became broken.

Signs of storm slab instability were prevalent while breaking trail. Cracking occurred within the most recent new snow from last night, staying above the sun crust formed yesterday. This storm slab instability was failing on an upsidedown new snow structure of denser snow on top of less dense snow from the start of last night's snowfall. The vast majority of cracking we triggered was within last night's snow. Only on rare occasions did we trigger cracking down through yesterday's storm snow to just above the crust below. This deeper failure is where storm slab avalanches were failing yesterday on non-persistent snow grains. Cutting the top of test slopes we were able to trigger some shooting cracks up to 2m long.

Blowing and drifting snow was prominent during the morning hours of snowfall and continued into the early afternoon hours when snowfall had stopped and the sun started to come out. We observed along the ridgetops a shift from SW to W winds and some redistribution of snow on the ground as a result. Cornices were fragile and were easy to fracture above test slopes, sometimes cracking significant distances (see photo). Wind slabs were present in the areas where drifting snow was depositing. We were able to trigger a small wind slab avalanche on wind loaded test slope.

With signs of instability in plain sight, we stuck to sub 30 degree slopes in areas of consequence. As we exited the area in the early afternoon, some minor sun effect was noted on E aspects, but not enough to create warming instability.