Mystery boom in Indiana
An unexplained "boom" is causing confusion across our viewing area, as we've had reports of homes shaking, a loud boom, and no visible sign as to what could have caused it.

People from Warsaw to Mishawaka and up into Michigan are describing a boom that occurred around 6:30 Sunday night.

Every person WSBT 22 talked to said it seemed like it was very close by and many of them compared it to an explosion.

"I heard a boom and it wasn't a firework, it wasn't a gunshot," said Evan Bordner, who heard the 'boom.' "It went on for a little bit. It extended out for a little bit."

It's a sound Mishawaka resident Evan Bordner describes as an explosion.

"I live across the street from a place that fills and distributes propane tanks," said Bordner. "I was thinking something had gone wrong over there. I was like 'Oh no!' But a couple seconds, no yelling, no nothing, so I just thought 'Oh well.'"

He's not the only one.

"It rattled my dogs and they go barking to the front door to see if there is somebody outside," said Elizabeth Brownbridge, who heard the "boom." "I said to my husband, 'Did you hear that?' And he's like 'No.' And I'm like 'That boom!' And he's like 'Yeah, I wondered what that was.'"

WSBT 22 has received numerous messages from people reporting Sunday night's strange occurrence, and they were all throughout our viewing area.

The "boom" was caught on video by Kristen Roth at Winona Lake.

So what could it be? WSBT 22 meteorologists have ruled out a frost quake, when water freezes quickly underground.

The USGS is not reporting any earthquake activity in our area.

Physics Professor Henry Scott says the sound in the video doesn't match solar events.

"That's strange sounds," said Scott, IU South Bend. "It's short duration, kind of higher pitched sounds."

He also says a meteor shower or a solar flare are most likely not the culprit.

"If it were something like a meteor, I don't think it would sound like that," said Scott. It would have been a longer rumble. But a meteor would have been observed. There would have been something that lit up the sky."

Are more booms possible? Brownbridge says Sunday night's wasn't the only one.

"It sounded like it was like a block away. It was really loud. The one this morning kind of shook the house a little bit," said Brownbridge.

More people have reached out to WSBT 22 Monday, saying there was more than one boom.

Calls to the Grissom Air Force base have remained unreturned.

But WSBT 22 did have people tell us they saw helicopters in the Warsaw area Sunday night, so right now, the mystery remains.