RUTHERFORD COUNTY, TN (WGNS) - If you heard a sudden boom Monday night — or even felt your house jolt — you weren’t alone. Residents across Rutherford County phoned and emailed WGNS with reports of loud cracks, thuds, and what many thought were blown transformers or distant explosions. But the real culprit wasn’t electrical at all. It was the weather.

What folks experienced were frost quakes, a rare but perfectly natural phenomenon that tends to show up during extreme cold snaps like the one gripping Middle Tennessee. The National Weather Service explains that frost quakes, also called cryoseisms or ice quakes, happen when the ground is saturated with water from rain, melting snow, or ice. When temperatures drop rapidly — often within just a few hours — that water freezes so fast it expands with enough force to crack the surrounding soil and rock.

That sudden cracking is what produces the startling boom, sometimes accompanied by a brief vibration that can feel like a small earthquake. Because the rupture happens close to the surface, the sound carries easily, especially on quiet winter nights when everything else is still.

Rutherford County had the perfect recipe: days of melting snow followed by a sharp plunge into single‑digit temperatures. With the ground soaked and unprotected by a thick layer of snow, the freeze happened quickly, setting off those loud, isolated pops that had so many people peeking out their windows.

Frost quakes are most common in colder regions like the Northeast and Canada, but they can happen anywhere conditions line up just right. The good news is they’re generally harmless, though they can occasionally leave small cracks in soil or pavement.

So if you hear another boom during this cold stretch, it may just be the ground adjusting to Tennessee’s wild winter mood swings.