It started with this email from a listener:
"At exactly 5 this morning, I was awoken by what sounded like several explosions in or around Rock Island. I don't know if you talked about it at all, or heard it yourselves. I thought it was simply thunder, but there were no follow up sounds for 15 minutes afterwards when I fell asleep again. Any ideas what it was?"

Here's more:
"I can back this guy up. I was woke up at 5 a.m. on the dot by what I text my girlfriend as the longest loudest single thunder I've ever heard the and never heard a follow up thunder.  My house was literally shaking and vibrating too."

"Dear Dorks,
The volume of thunder depends on how close you are to the lightning strike. There is no way if lightning strikes in Rock Island, it's going to be just as loud in Sterling and Geneseo, and there is no way the longest roll of thunder ever happened in several different areas."

Well, lots of people heard it…the same massive boom was heard and felt in Dewitt, Clinton and all the way east toward Sterling and Geneseo.  That's a really big area.  And, it really was THUNDER.  As one listener pointed out, how could people experience what most were telling us what sounded like an explosion or the "loudest thunder I've ever heard" over such a vast area?  Rather than try to explain it, I'll let James Zahara take a crack art it (since it involves science and other smart-people stuff):