I read a study somewhere that when high surf suspends upper layers of organic sediment in the water it can increase bacteria counts in the Gulf (especially around the Mississippi delta). Maybe the combination of high runoff and high surf had a double whammy effect. This settles down fairly quickly when the surf drops. On the other hand, I'm sure there have been other periods of high surf and high rain without producing poor water quality result tests, so I still think this is a puzzler.
Just an opinion - When the coastal dune lakes break open there will be a great deal of lake water flowing into the gulf - I know from living on Eastern Lake, many residents still have septic tanks and with all the rain over the last few weeks the ground is saturated. I am not a scientist by any means but when you have the amount of rain and the lakes draining into the gulf, this has to contribute to the bacteria levels being measured. If you walk behind One Seagrove Place, there is a major drainage pipe that flows water from 30A into the gulf as well. How that was approved is beyond me..