Loud Booms and Light Shaking Caused by Frost Quakes

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Meteorologists say that water rapidly freezing in the soil amid bitterly cold temperatures can make a startling noise and even cause small vibrations, known as frost quakes or cryoseisms. This 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.

Why it matters

Frost quakes are a relatively rare occurrence, especially in some regions like Kentucky, where the weather does not often get cold enough for the soil to freeze that quickly. While the noises can be startling, especially at night, meteorologists say they are generally harmless and not a major cause for concern compared to the bigger dangers of bitterly cold temperatures and wind chills.

The details

Evan Webb, a meteorologist with the National Weather Service in Louisville, Kentucky, said the office has received reports of 'loud booms' that are associated with cryoseisms during bitter cold weather. Webb noted that some people may initially wonder if the noises are from an exploding tree or something similar. He explained that frost quakes are 'mostly harmless' and that single-digit temperatures with a wind chill are a bigger concern.

• When temperatures rapidly fall below freezing.