Buried Surface Hoar Observations on Yuba Pass

We went back to the Yuba Pass area to revisit locations where the Jan 29 buried surface hoar layer seemed to be the most reactive and largest in size throughout the forecast region.  We went to some of the same field locations that a previous observation from Monday Feb 6 showed instability and unstable snowpack test results, see observation from Monday Feb 6 here:  https://www.sierraavalanchecenter.org/observation/2023/feb/6/1200/lincoln-ridge

We were able to easily identify the Jan 29 buried SH layer in these areas, but a lot has changed since Monday.  Moving through northerly terrain we were not able to get any collapses or whumpfing sounds, these were widespread on last Monday in similar terrain.  The Jan 29 layer has gained strength and has integrated more into the snow above and below it.  2 ECT's showed no propagation with ECTN's on a density change in the Sunday storm snow.  This layer does remain large in size with surface hoar up to 1 to 2.5cm, but some of this layer has laid down or collapsed since the Monday observation.   Overall, this layer was unreactive at this location.