First Alert Weather

Did You Hear a Mysterious Boom Last Night? It Could Have Been a Frost Quake

Frost quakes, or cryoseisms, may cause shaking and loud noise, but they don't tend to cause big damage

NBC10 Boston

Were you woken up by any loud booms last night? Residents in New Hampshire reported the blaring sounds thinking it was their roof coming apart or a big earthquake. While this phenomenon may be strong enough to rattle houses and resemble an earthquake by shaking and producing loud sounds, frost quakes, or cryoseisms, happen at higher ground and fortunately don’t tend to cause big damage.

These occur when the ground experiences a sudden deep freeze, just like what happened yesterday and what’s about to happen again tonight. With the melting snow and rain that fell yesterday, the water easily seeps through the ground. But late at night, when temperatures dip to subfreezing, the water underground will also freeze and expand. Think of it like an ice cube, when that water freezes, the density of water will decrease but the volume will expand up to 9% of its size. That’s exactly why you hear those loud breaks and booming sounds as the freezing water is trying to expand below ground.

They tend to happen after midnight when temperatures grow colder. We’re having lows in the 20s again tonight, meaning that frost quakes may occur again, except now it won’t catch you by surprise.   

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