Residents of Bozeman and the surrounding Gallatin Valley have been hearing loud, concussive booms with no obvious source. According to Distinctly Montana, reports picked up in mid-2025 and continued through August 2026. On August 18 one Reddit user logged a boom at 11:26 p.m. near Ferguson and Babcock.

Montana has a long record of these. On July 4, 1805, Meriwether Lewis wrote of repeated booms near the Great Falls of the Missouri, like a six-pound cannon three miles off. “I am at a loss to account for this phenomenon,” he wrote. In June 2022 a boom near 6 p.m. was heard from Bozeman to West Yellowstone and Livingston. Billings had a run of unexplained bangs in early 2023. In January 2024, Ravalli County’s sheriff was flooded with calls about one blast, and some witnesses said they saw a meteor first.

Locals have offered plenty of explanations: trains coupling, transformers blowing, sonic booms, Tannerite targets, homemade fireworks and kids setting off flash-powder salutes. None has been confirmed for the current run. The article reports that local police have asked residents to stop calling to report explosions around town.

No agency has published a cause. Booms like these are often traced, eventually, to something mundane. In Bozeman, that something hasn’t been found.