Just another afternoon in Interzone:
On February 3, 1969, people on Jacksonville Beach began hearing strange rattling sounds coming from the sky. They gradually realized, so the story is told, that the sound was specifically emanating from two clouds passing directly overhead.
A newspaper article quoted an eye(ear?)witness as describing the sound to be "like constant crumpling of cellophane." Another described it as like the noise of someone "walking on pebbles," only magnified. There were no unusual weather conditions, nor any other reason for the sounds, try as the authorities did to find an explanation for the rattling clouds. A police captain followed one of the weird clouds for a short time until it abruptly dissipated and vanished.
And then a week later, it happened again - this time in Miami Beach.
Of course, an "official explanation" just had to be cobbled together, as it always does, no matter how preposterous. It was decided, by those who decide such things, that all these people, including a police officer, simply mistook the sound of the surf reflecting off the clouds (vapor is not especially noted for its sound-reflective properties) due to "some kind of temporary inversion of sound." As Will Smith once said to Tommy Lee Jones, "...and that weak-ass story is the best you can come up with?"
So..... what the heck was going on here? Ours is not to question. Drink up.