No injured cavers recorded.
Two cavers attempted the near-sump at the upstream end of Logsdon River in the Roppel Section of Mammoth. In the 30 foot wide passage the ceiling comes very close to the water surface as far as one can see. The cavers worked their way along to only one and a half inches of air space but could find no way to continue. One lost his way in the wide, featureless pool and exited the wrong way. He reached no air space, then a mud bank which told him which way to go. It was a close call indeed.
They decided that such sump pushing was close enough to real cave diving to demand cave diving safety practices, such as a line to define their route.
Near-miss during sump attempt with minimal airspace; emphasizes need for cave diving safety practices.