Burlington, VT – Vermonters from Burlington to Montpelier could soon be startled awake by loud, thunder-like booms echoing through the night — but it’s not construction or an earthquake. The Vermont Geological Survey says these mysterious winter noises are likely frost quakes, or cryoseisms — a rare phenomenon caused by rapidly freezing ground.
Frost quakes form when moisture in the soil freezes too fast during sharp temperature drops. As that trapped water turns to ice, it expands, putting intense pressure on surrounding rock and soil until it suddenly fractures — releasing a loud “crack” that can sound like an explosion and, in some cases, shake nearby homes.
Meteorologists say the setup for frost quakes is becoming more common in Vermont: wetter fall conditions, limited snow cover, and rapid plunges from above freezing to below zero within a day. That combination allows frost to penetrate deeply into saturated ground.
According to weather experts, Chittenden, Washington, and Addison Counties are most likely to experience frost quakes this season, especially during overnight cold snaps when temperatures dip into the single digits. Most occur between midnight and dawn, when the cold is most intense.
While these events rarely cause damage, they can leave small surface cracks in driveways or frost heaves in yards. Experts recommend improving drainage and clearing excess water near homes before deep freezes arrive.
So if you hear a loud boom on a calm, icy night from Burlington to Montpelier, it’s not thunder — it’s the frozen ground beneath Vermont snapping under winter’s pressure.
