Observation: Public

Observation Details

Signs of Unstable Snow

Observations

Started at around 11 am in light rain. Several skiers heading out warned us of sloppy conditions, and one reported seeing a decently sized slide on Kendall Knob.

Headed up the wandering skin track into Commonwealth Basin. On the way in, snow was pretty light and fluffy, and there was at least 2' on top of the 12/21 crust. There were lots of large snow bombs falling all day, though there was no ice in them. As we headed up, the light rain switched to mixed snow/rain. We got up to 3600' (the Commonwealth log bridge) and dug a pit in an open patch between trees on a north-facing 30 degree aspect.

HS = 215 cm, and the top 3 cm were visibly wetting out due to rain as we dug the pit.

The top 80 cm was all storm slab sitting on top of the 12/21 crust. This top 80 cm didn't have any clear layering, and was consistently fist-firm. Beneath the 80 cm, there was a 3 cm ice crust sitting on a consistently wet and firm base.

Compression test:
CT-7 15 cm down in the storm slab, Q1, then successive breaks deeper and deeper, with a final cash drawer break on the 12/21 crust after 19 hits.

Extended Column Test:
ECTN-12, rough collapse, no propagation, 15 cm down into the storm slab.
Continued to ECTP-15, when we had a full propagation sudden planar collapse 22 cm further down in the storm slab (total 37 cm deep), which cash drawered out.

Based on these results and the worsening conditions, we decided to head home, and experienced horribly wet and heavy snow on the ski out.