Last winter's floods have made some changes inside Porth Yr Ogof. The floor of the main stream passage, between the Great Bedding Cave and the large aven area at Entrance I, has been scoured out and it is now possible to walk through upright, in chest deep water. Previously the water here had been waist deep and you had to walk through bent over, with your back against the ceiling. I'm not 100% sure but I think at least some of the scoured out material has been deposited near the final lake, just before the resurgence. I was told about this change a few weeks ago by an instructor so I'm sure the outdoor pursuits sector is aware for when they take groups through. Thought it might be of interest to others though.
I shot the little bit of video below yesterday, when the water level was very low, much lower than in Paul Marvin's recent video of the cave. The entrance at the start is Entrance I, as marked on the survey and we were heading back upstream.