Meteorologists say that water rapidly freezing in the soil amid can make a startling noise and even cause small vibrations.
These noises are known as frost quakes or cryoseisms, a cold-weather phenomenon that occurs when rain or melted snow in the ground quickly freezes, expanding as it solidifies, when temperatures rapidly fall below freezing. As the ice expands, pressure builds around the surrounding soil, causing it to crack and make booming sounds and light shaking.
Evan Webb, a meteorologist with the National Weather Service in Louisville, Kentucky, said the office has received reports of 鈥渓oud booms鈥� that are associated with cryoseisms during bitter cold weather.
鈥淚 think some people initially wonder if it鈥檚 an exploding tree or something,鈥� he said.
Webb said frost quakes are 鈥渞elatively rare, especially in Kentucky 鈥� we don鈥檛 get quite cold enough very often to have saturated soil in the winter time to be able to freeze that quickly.鈥�
Webb said frost quakes are 鈥渕ostly harmless鈥� and .
The weather service office notes in a social media post that the noises can be startling, especially when they happen at night, but they’re generally not a cause for concern.
鈥淭hose loud booms aren鈥檛 paranormal鈥攖hey鈥檙e cryoseisms (Frost Quakes)!鈥� .
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