Jean Swesey was doing homework with her son in Cottonwood when it happened.
"It was a whole series of booms," Swesey said. "Up to six or seven. It was fast, it went loud. We were quiet and then my daughter down the hall screams really loud, ‘Did you hear that?' I sat there for a second and I heard another set."
Swesey wasn't alone. Residents in communities in and around Verde Valley and as far as Flagstaff called 911 or their police and fire departments to report the strange booming sounds.
"It sounded like thunder, but underground," Swesey said. "Like muffled thunder. And all the dogs in the neighborhood, all of them that were outside all started barking at once."
CBS 5 News first received reports of the explosion-like noises shortly after 5 p.m. Tuesday and began checking with law enforcement and government sources. The U.S. Geological Survey reports no significant earthquake activity in Arizona that could have created the booms.
The Yavapai County Sheriff's Office had deputies in the area who either heard it or tried to respond to resident calls. They found nothing.
The Sedona Fire District dispatched a crew to check a report of a strange odor, but that was unfounded and may not be related to the sounds.
The Camp Verde Marshal also received a number of phone calls about the booms. Officers found no evidence of any explosions.
But the Verde Valley contains large expanses of uninhabited land. "Maybe when the light comes back they'll find something," said Gary Johnson of Sedona Fire.
Swesey sure hopes so. "It was just, ‘boom-boom-boom-boom-boom all over the Verde Valley."
“We started getting calls at 3:09 p.m. (Tuesday),” said Eric Meyers, Navarro County Emergency Coordinator. “The first calls were north of Corsicana in the Hickory Hollow area with two separate residents out there reporting unusual tremors being felt along with a rumbling type of noise.”
“About two hours later, approximately five o’clock, there were additional reports in the same area of heavier tremors, the same vicinity, the same residents,” Meyers said. Another report came from the western part of the county, near Navarro Mills.
After the second round of reports, Meyers posted it on Facebook and suddenly there were more reports, but coming from all over, including Streetman, Purdon, Pursley and Dawson. Some of the reports came from as far away as Freestone and Limestone counties. The line runs about 50 to 60 miles long, and the tremors didn’t act like any other thing except perhaps earthquake booms, which are shallow sometimes undetectable tremors similar to what’s been happening locally.
“This is an unexplained event likely of a natural origin,” Meyers said. “We can’t come up with a point of origin or a cause or explanation of why this is happening.”
“We were trying to determine what was going on, any type of military exercises at a higher level than locally, we worked on this throughout the night and we eliminated everything we could think of and continued to do some through today,” Meyers said.
“We went through the process of elimination on what it could be and ruled out all these different things,” he said. “Whatever it was hasn’t occurred since 4 a.m. Wednesday. It’s unusual, to say the least.”
Just before midnight on Monday, reports of a loud boom flooded police stations and social media sites alike.
Sources from the Warwick Police Department said they received nearly 100 phone calls reporting a loud noise that some thought was an explosion. Some residents called to say it shook their homes.
On the other side of Narragansett Bay in Barrington, residents also reported the noise, and a few said a flash of light accompanied it.
The calls prompted an initial police and fire search of the areas, and then marine crews took to the waters between Conimicut and Bullocks Point to search for the source of the sound. Senior Chief Jamey Kinney, from the southeast sector of the Unite States Coast Guard, said one of their boats from Castle Hill joined four other local boats to comb Narragansett.
Initially, the Coast Guard made calls to T.F. Green to see if they had any missing planes, but the FAA confirmed all was status quo. They also reached out to National Grid to see if any transformers had exploded, but they, too, confirmed all was well. The Coast Guard then tossed around the idea that the noise could have been a vessel in distress, but Kinney said their foray into the waters was more as a precautionary measure.
“It’s better to respond earlier,” said Kinney.
But there was no vessel, and after combing the waters for an hour and 50 minutes the Coast Guard returned their team to shore empty-handed.
To add to the mystery, residents further reported a low, droning, humming noise coming from the water that began about an hour or so after the initial boom was heard, about the same time crews took to the water to comb for a source.
Some on social media said the hum sounded like a distress signal, while others said it didn’t sound like anything they’d heard coming from the bay before. One person said it sounded like it could be a tugboat. But Kinney said the source of the hum is just as mysterious as whatever caused the initial boom.
Locally, reports of the boom came from local neighborhoods like Buttonwoods, Hoxsie, Conimicut, Lakewood, Edgewood, Warwick Neck, Gaspee and Governor Francis Farms. Other media outlets have reported that the noise was heard as far away as Somerset, Mass. Yet, there were still some residents of those communities that missed the boom altogether.
Though Kinney said, “strange stuff happens all the time,” he has never heard of mysterious boom like this in this area.