Sib Ridge Bowl Pit & Natural Avalanche Activity Observed

AST 2 course observation - we believe this to have failed on the January weak layer of facest and depth hoar - We saw 2 PS of note in the same area on the NE/E aspect of Mammoth head (above "mosse droppings") that were size 1.5-2.. Many ST size 1-1.5 scattered about in the same area (photos included here). We dug a pit right outside of the ski area boundary in simple terrain and had drop/pops/proppgation results on the storm snow and PS - making another post for this. Please have a closer look at my photos for more accuracy, as this is my first post being made reporting a natural avalanche. Thanks for the helpful criticism!