What Was That Noise? Bozeman's (and Montana's) Mysterious Boom

By Sherman Cahill | August 27, 2026

Until recently, if I had heard the words "Bozeman" and "boom," I would have associated it with the almost obnoxious growth of what adherents and opponents alike dub "Bozeangeles." But in recent years it has come to have another meaning: an unexplained concussive noise heard in the Gallatin Valley and even sometimes beyond, which wakes residents in the middle of the night. It has, as of the time of this writing, become so common and so vexatious to the local constabulary that they have asked townsfolk to please stop calling them to report it to the police. The police, to be clear, are not interested in your reports of explosions about town.

This writer experienced it himself, one evening in the early 2000s. I was staying with my grandparents at the tender age of 13 or 14; I had been sleeping on the sofa bed of my grandpa's office, watching something on TV or reading, when a large, well, boom rattled the windows and made me bolt upright. I looked out the window, threw open the door - what was that noise?

Since then, I've written it off as a sonic boom, probably the result of a jet flying over. But then, jets have a roar, don't they? And no sound preceded this boom. It came, seemingly, out of nowhere.

Now the Bozeman boom is a named phenomenon, frequently discussed on social media, where posts track the sounds and folks all over town report where they heard them. There was a boom on June 5, 2022, at nearly 6 pm. A loud, cacophonous noise was heard in Bozeman, Belgrade, Four Corners, West Yellowstone, and Livingston, with no official cause ever discovered. Then the booms picked up in mid-2025 and have extended through August of 2026. It seems likely it has extended through to whenever you are reading this.

On the r/Bozeman Reddit page, amateur investigators clamor to capture the boom on their Ring cams. On an August 18 post entitled "Boom 11:26pm near Ferguson and Babcock," Reddit user BryanBryanBryan123 posted, "I actually just heard a bozeman boom for the first time ever, didn't think they were real[.]." On that same post, user Pristine_Outcome3535 asked, "Is anyone tracking or mapping the booms?" Someone replied that yes, they were going to start trying.

It may be, however, that the mystery isn't specific to Bozeman; on January 3rd of 2024, the Ravalli County sheriff's department was inundated with calls after a large, unexplained boom was heard. Some reported having seen a meteor before the noise, suggesting one possible explanation. Nearly a year earlier, in February of 2023, Billings was plagued by recurring bangs heard as far away as Blue Creek. There was no explanation.

Or rather, no explanation seemed to satisfy all of the properties of the booms. Trains coupling, transformers exploding, sonic booms, Tannerite explosions, gunshots, and even unstable meth labs have all been proffered, but none cover the whole phenomenon. Especially when you consider it may have started centuries ago.

On the fourth of July in 1805, after the Corps of Discovery had reached the Great Falls of the Missouri and nearly completed the arduous task of portaging them, the journals of the explorers report something strange.

Lewis described it thus: "since our arrival at the falls we have repeatedly witnessed a nois which proceeds from a direction a little to the N. of West as loud and resembling precisely the discharge of a piece of ordnance of 6 pounds at the distance of three miles. I was informed of it by the men several times before I paid any attention to it, thinking it was thunder most probably which they had mistaken[.]"

Clark corroborates, writing in his journal about "...a rumbling like Cannon at a great distance is heard to the west of us; the Cause we Can't account."

They could find no explanation for the sounds. Lewis first assumed it was water accumulating and suddenly emptying in a cavern somewhere in the nearby mountains, but then reasoned that something like that would discharge regularly. However, this noise was "sometimes heard once only and at other times, six or seven discharges in quick succession."

Ultimately, Lewis was left to state that "I am at a loss to account for this phenomenon."

Further trappers and settlers would confirm the sound, an explosive report comparable to a sonic boom. But Montana in 1805 certainly didn't have any gun big enough to make a noise like that, nor did it have anything that would repeatedly produce a sonic boom. And the area around Great Falls isn't the only place in America that hears similar noises. Some call them "mistpouffers" or "skyquakes," but they are described as being like large ordnance nearly everywhere they are reported. In upstate New York, people have been hearing very similar sounds for centuries, first by Native Americans, and then by settlers. They became known to New Yorkers as the Seneca Guns, owing to their auditory resemblance, once again, to cannons firing. James Fenimore Cooper even wrote a story about the noise, called "The Lake Gun."

In Bozeman, though, there are some that think they can offer a prosaic explanation, at least to some of the more recent rash of booms. On Reddit, folks say that the boom is sometimes preceded by a flash. Others say that the booms are followed by the sound of a truck speeding away. On one post, acetylene bombs are suggested, along with the claim that someone blew up a portapotty behind Costco with one. Several other users confidently assert that they are salutes, ground or aerial fireworks that flash by igniting flash powder - the work, that data might suggest in either case, of bored kids.

Perhaps prankish teens are enough to explain away the recent rash of Bozeman booms, but the idea is less picturesque, and marginally less terrifying than, say, the idea that the elite are tunneling under the mountains, carving out tunnels in which to survive some upcoming armageddon. Naturally, that is yet another of the posited solutions, and not even the least plausible.

But neither pranks nor occulted goings-on can explain what Lewis and Clark heard on the 29th anniversary of our nation's independence, all of those years ago. For now, some number of the Bozeman - or rather, the Montana booms - remain unexplained. Perhaps someday we'll know what they are.

Until then, as Reddit user CMPilot eloquently put it, "The BOMS are here in force! BOOM BOOM BABY!"