Milwaukee, WI – Residents across Milwaukee and Madison could soon hear thunder-like booms echoing through the night as temperatures plunge. According to the University of Wisconsin–Milwaukee’s Geosciences Department, those startling sounds are likely frost quakes — sudden cracking events caused by frozen, water-saturated ground under intense pressure.
Frost quakes, or cryoseisms, occur when moisture seeps into the soil and then freezes too quickly. As the water expands into ice, it pushes outward until the frozen ground suddenly fractures, releasing energy in a sharp, explosive burst. The sound can resemble a gunshot, thunder, or even a small earthquake, often strong enough to shake nearby windows.
Meteorologists say Wisconsin is set up for prime frost-quake conditions this winter. After a stretch of mild, wet weather, an incoming blast of arctic air is expected to drop temperatures from near freezing to below zero in less than 24 hours. That rapid freeze, combined with minimal snow cover across southern Wisconsin, could create the perfect environment for frost quakes from Milwaukee to Madison.
These events usually happen overnight, between midnight and dawn, when the cold is most intense. Though harmless in most cases, frost quakes can leave small cracks in driveways or frost heaves in the ground.
Experts recommend improving yard drainage and moving standing water away from foundations before the next freeze.
So if you’re awakened by a thunder-like boom on a calm, icy night in Milwaukee or Madison, it’s not an earthquake — it’s winter itself, cracking beneath your feet.
