Clearwater, Florida -- A smoke ring rising into the sky kept Facebook, Twitter, and our phones at 10 News busy Thursday evening as folks tried to figure out -- what caused it?
Photos of the thin, black hoop of smoke flooded in from all over northern Pinellas County: Safety Harbor, Countryside, and other Clearwater neighborhoods.
Jimmy McCallum watched it rise from U.S. 19. He says it floated for a few minutes, then dissipated.
Where did it come from?
We called the National Weather Service and Pinellas County emergency dispatchers. They had no answers.
There are wild machines out there that people build for fun -- massive blowtorches that send a black ring into the sky.
Our research found this ring spotted over Chicago three years ago. It's remarkably similar to the one seen on Thursday around sunset hovering over Pinellas County.
Except we definitely know what caused the ring in Chicago -- and others like it in Texas and Oklahoma: an exploding electrical transformer.
The transformers you would see in your neighborhood are big gray cylinders hanging from power poles.
They're perhaps the size of a water heater from your garage, but much fatter. And they make ones that are a lot bigger, too.
When transformers blow, they can send off a boom or bang, like a 911 caller from Clearwater reported on Thursday.
The typical shape of transformers -- a cylinder, like a soda can -- has a perfectly circular opening at the top.
It's exactly the shape that could send out a blast of smoke in a perfect circle, creating a mysterious ring rising into the sky.
We put called Duke Energy and the Tampa Electric division of TECO Energy, but neither power company had reports of a blown transformer.
There may be other transformers in that area, though, that are owned by private companies. We'll continue to dig into this mystery.
Grayson Kamm, 10 News