Some strange booms have shaken residents in Fond du Lac County.
The series of explosion-like sounds rattled residents from Waupun, Campbellsport and elsewhere Tuesday and sent Fond du Lac County sheriff's deputies out looking for a cause.
Geologists say the booms were likely a phenomenon commonly known as an ice quake. It's caused by water that sinks into the soil and bedrock where it freezes and expands, causing an explosive popping sound that feels like a mild earthquake.
University of Wisconsin-Milwaukee seismologist Brett Ketter tells Action Reporter Media he experienced an ice quake this week and initially thought the pipes had burst in his house. Ketter says he ran outside in his slippers to see if something had hit his house.