The buried surface hoar as you mention is about 12 inches down and on some slopes and not on other slopes. This layer when present, propagetes with the ECT at 20 wacks. On the northeast side of steam mill peak (100 vertical ft. below the peak, a pit found another surface hoar layer at 24 inches. This was not sensitive to ECT wacks but impressive size flakes scaring when it did come out with a shovel shear.

moderate to considerable when the surface hoar is present if you can figure that out all the time!