Approached steep wind-loaded convex roll cautiously looking for wind slab. From 25* slope remote triggered a SS-AScr-D1.5-R3-I, 38*, 30-60 cm deep x 150' wide, at 7,300' N-NE. Investigation of the crown/weak layer/bed surface determined the weak layer was a 15-20cm layer of 1mm FCsf (likely formed during the cold period early this week, I noted surface faceting/weaking during that period). Small grained FCsf may heal quickly, but also may be reactive for now. I also noted easily failing SS on 35-38* rolls in lower LCC protected N facing slopes at ~8,200' on 1/26 and suspected these to be failing on some FCsf.