Observation: Public

Observation Details

Signs of Unstable Snow

Observations

The storm continued to snow low density snow all day Sunday. Pulsing with heavy rates of snow (S2) at times and (S-1) most of the day. A few short breaks did allow the disk to burn through the clouds. 44cm of storm snow has been deposited since Friday morning above 6000ft. Cooler temps and light winds all day. Somes gusts were contributing to transport ATL but the snow was only slightly more cohesive and the wind effect was minimal.

A distinct interface between the two storm waves in the most recent snow did present itself when traveling , in shovel tilt test, and in easy compression tests. The lack of cohesion in the upper-layers of low density snow would not propagate a fracture. The poor bond in the interstorm layers did contribute to long running dry loose avalanches in steep terrain.

Pit Obs: HS 260cm; NTL 6500-ft on solar/southwest aspect
The reactivity of the Jan 30th surface hoar (SH) is subsiding. This persistent layer is now 50-60cm below the surface and was responsible for many skier triggered avalanches early last week and friday. The current stubbornness of the layer would not allow for propagation in this drainage east of the crest. There are other reports with similar findings further west and at crest. The facets near to the Jan 24th crust, deeper in the pack 75cm down, were not reactive in this pit.

The most noticeable layer was a supportive MF-crust under the new storm snow. This layer tapers out around 5500ft. This crust did have a weak structure but did not appear to be contributing to the avalanche problems of the day.