Philadelphia, PA – From Philadelphia to Pittsburgh, Pennsylvanians may soon hear loud, explosive booms echoing through the night as temperatures plunge. According to the Pennsylvania Department of Conservation and Natural Resources (DCNR), these startling sounds are likely frost quakes — sudden cracking events that occur when frozen ground splits under intense pressure.
Known scientifically as cryoseisms, frost quakes form when rain or melting snow seeps into the ground, then freezes too fast during an arctic cold snap. As that water expands into ice, it creates powerful stress until the soil or rock fractures, releasing energy with a loud, thunder-like crack.
Meteorologists say this week’s weather pattern — mild rain followed by a sharp drop into the teens — makes conditions ideal across much of the state. Areas with little snow cover, including parts of eastern and southwestern Pennsylvania, are especially vulnerable since snow normally insulates the ground from deep freezing.
Frost quakes typically occur between midnight and dawn, when temperatures are lowest. While the events are brief and rarely damaging, they can rattle homes and sometimes cause small cracks in pavement or driveways.
Experts recommend clearing standing water and ensuring proper yard drainage before deep freezes to reduce risk.
So if you hear a thunderous boom on a calm, icy night from Philadelphia to Pittsburgh, don’t panic — it’s likely Pennsylvania’s frozen ground snapping under the weight of winter.
