Nearby lightning strike?
Didn't sound like one of those either.
A Canadian friend who used to spend long periods over here was a Scimitar GTE fan. He owned several, wanted to take at least one back to Canada but the red tape put him off. One late evening driving across near the top of a local hill there was a very loud bang and the car jumped sideways a foot or so. He could find no marks on or under the car and eventually came to the conclusion it was a close lightning strike.
