Observation: NWAC Observer

Advanced Information

Weather Summary

Overcast. Fair visibility, with filtered sunlight through ongoing light snow fall. It seemed that most wind transport occurred overnight on Jan.30 into the AM of Jan.31, with minimal transport observed under light winds today.

Avalanche Observation Comments:

No recent avalanches observed

Snowpack Observations

We ski tested steep slopes on polar and solar aspects, within the Below Treeline and Near Treeline elevations bands, with surprisingly no dry loose activity. Wind slab was also surprisingly very isolated or absent, but we probably could have found it, adjacent to alpine ridge crests. Overall, we found a better-than-expected bond with the recent storm snow and the Jan.30 crust interface.
Profiles on colder aspects, unsurprisingly, show the most-suspect structure, especially Below Treeline. Here, thin freezing rain crusts overlie weak facets and thicker melt-freeze crusts. This assemblage may persist and be prone to collapse, given adequate loading over time. Patchy surface hoar was identified, here and there, at the crust interface.
The solar aspects hold a very strong snowpack, with a stout melt-freeze crust up to 20cm thick overlying small rounded grains with some moisture content. The previous crust surface is generally rough, allowing for a favorable bond with the recent storm snow.

Avalanche Problems

We found no avalanche problems, over a couple of field days in the area. However, we suspect that wind slab exists in the alpine, and we avoided steep slopes adjacent to ridge crests above treeline, where a skier-triggered slab could result in a long and fast ride over firm surfaces.