Observation: NWAC Observer

Advanced Information

Weather Summary

Cold air remains entrenched over Lake Chelan and this tributary, the valley of Railroad Creek. Below approx. 4500', temps. have hovered in the low-teens F, while above, in our field location today, temps. were in the mid-20's F. The ongoing storm did not really kick-in until after mid-day. Filtered sunshine existed above the inversion, until the wall of cloud arrived.

Avalanche Observation Comments:

No recent avalanches observed, but very small crowns (<5cm) were evident on micro-terrain features in the PM, where the HST was failing on the SH, but not running any distance.

Snowpack Observations

We targeted the Solstice Crust with a profile at 5800' on a S aspect. In our pit, the HS was 110cm, the crust was down 40cm, and produced no results in tests.
On an E aspect at 6200', we found the Early December Crust down 120cm in a pit with an HS of 160cm. We found a well-bonded interface that failed to produce results in Deep Tap tests.
We ski tested very isolated older wind slabs at ridge crest locations near and above 6000', finding them unreactive or stubborn and of very limited extent.

Overall, the lower-and mid- snowpacks observed within this watershed are strong and lacking in problematic layers. The upper snowpack is, of course, weak, with surface hoar (where it exists) now buried beneath low-density storm snow. This structure is most prevalent Below Treeline. Specifically, we found the most-consistent deposits of large, flay-lying surface hoar within sparse, previously-burned forest below approx. 4500' on southerly slopes.
See photo, from the AM prior to burial by storm snow in the PM.

Avalanche Problems

Storm Slab likely developing overnight with increasing snowfall intensity