Sonic Boom reported as National Guard does night training in area

Residents in western Fond du Lac and eastern Green Lake Counties were shocked when a sound that was described as sounding like an explosion took place Monday night, March 9, 2026.

Just before 9 p.m., the Fond du Lac County Communications Center received numerous calls of an explosion in Waupun. Residences say the sound shook their houses, yet nobody could see anything out of the ordinary.

The Waupun Police and Fire Department were sent out to investigate but nothing was found.

Minutes before the sound, jet engines could be heard high above in the sky, and it was determined this was a sonic boom from one of them. This theroy was further confirmed when Waupun Fire Chief BJ DeMaa advised the communications center of a post he saw online stating there would be night time military training exercises over the area.

Looking into this, KFIZ found a statement from The Wisconsin Air National Guard’s 115th Fighter Wing in Madison saying they would be conducting nighttime F-35 jet training this week, Monday through Thursday, and residents in the Madison and surrounding areas, including parts of east-central Wisconsin would hear the jets overhead.

While sonic booms are generally prohibited over land and populated areas, the National Guard says they can inadvertantly happen from time to time as pilots approach speeds that break the sound barrier.

Residents in the county should stay aware through Thursday that another sonic boom could occur.