Typically, the basin and and cavern zone which is big go black while the upstream might be clear in rainy conditions. In this case the deco is a zero viz situation from 130' to the surface. Like Cathedral, Eagles Nest and some other sites this is a non-starter especially with divers that have no previous experience at this site. Also, with the rains, the water temp in the cavern zone can be as low as 55'-60' Not a dive stopper but mighty unpleasant for a 1 hour deco if you have not prepared in advance. Also worth noting, getting in and out of the sink becomes somewhat hazardous with rainfall. Granted there are steps now and mitigate the dangers of injury. The steps are not and can not be made ADA safe in the manner of Peacock and other sites as the terrain prevents this. The bottom line is that I will not dive there if a downpour is expected as the conditions within the cavern can and will change quickly. I say that as both a diver and guide at Mill Creek Sink. Rob Anderson is the property manager of Mill Creek and can answer any questions regarding diving at this site. It would be best to contact him directly to organize a dive at Mill Creek rather than rely on the comments here. Alternately, I am available for discussion via PM.

Best Regards, Frank Ohidy, ex Program Director, NSS- CDS BoD.