A roaring sound heard throughout southern Wisconsin on April 19, 2015, has anxious residents mystified and seeking answers from authorities. The sound, described as “louder than a jet airplane” and lasting for 2-3 minutes, was heard around 8:15 PM in the cities of Beloit, Elkhorn, Delavan, Milton, Evansville, Albany, Monticello Monroe, Janesville, and other communities east of Milwaukee. One resident described the noise as “loud and constant” while another reported the noise was so thunderous, her house “vibrated”. One frightened family said they thought a large plane was about to land on their home.
A local Monroe man described the sound as similar to the deafening noise of a low flying commercial jet and noted that after about 3 minutes, it seemed to fade towards the west. A Monticello citizen said that at first, she thought the sound was a Harley motorcycle in her front yard. Social networks lit up with speculation and alarm as residents asked the obvious question – what was that mysterious sound?
The most likely explanation would be an errant, low flying aircraft but the Southern Wisconsin Regional Airport said no planes were flying through the airspace during the time the noise was heard. A radar controller in the airport tower told reporters,
“I heard the sound, too, and there weren’t any jets flying through or anything like that. If they would have come through our airspace, I would have seen it.”
NASA’s meteor tracking office was contacted and said there were no reports of a meteor in southern Wisconsin. They noted,
“The short answer is the sound likely was not caused by a meteor or fireball. Any noises produced by a meteor would sound like a sonic boom and last, at most, a few seconds.”
The National Weather Service in Sullivan reported no weather events or radar contacts (i.e. from aircraft or meteors) that could explain the noise and the U.S. Geological Survey ruled out earthquake saying there was no ground movement in the area on April 19 either.
Others proposed a transformer explosion (which would not have been heard over such a large area), secret military aircraft (or missing Malaysia Flight MH370) flying under radar detection (sound lasted too long for an aircraft flying overheard), or some unknown disruption in the upper atmosphere.
To date, the source of the window-rattling sound remains a mystery.