I get it now.
I never understood what people meant by thunder "rolling". I got the thunder "crashing" thing. In Toronto, a thunderstorm meant listen to what sounded like two enormous pot lids with paper lining being smashed together repeatedly until your head hurt so much you were considering hacking it off (you're welcome for that lovely image).
Here it really does sound like you are underneath some divine bowling alleyand it sort of rolls towards you then away from you and you are sort of concerned that maybe you hsould duck before you get hit in the head with a bowling ball.
Not nearly as loud or annoying for the most part, but it sures as heck does last a lot longer.