Missourians noted hearing bangs and crashes the past couple of days, the result of frost quakes from freezing weather.

Temperatures have hovered near zero degrees, with wind chill dropping them to 10-23 below zero, the National Weather Service’s St. Louis office posted on X.

When the temperatures plummet, groundwater can freeze and expand, pressuring soil above and bedrock below. Cracks develop and sound travels upward, heard as bangs on the surface. 

“Within the U.S., they happen most often across the central and northern Plains into the Northeast, but any place that can have saturated ground and rapid freeze cycles could experience them,” AccuWeather Senior Meteorologist Adam Douty said on the service’s website.

Loud noises were heard amid the cold snap across the middle of Missouri as well as in the St. Louis metropolitan area, according to the TV station KMIZ.

The NWS St. Louis office told KSDK that it received multiple reports of frost quakes but that the phenomenon is not actively tracked. The last confirmed frost quakes in the St. Louis area happened in 2014.

On Reddit, commenter bdginmo wrote Monday that “conditions were nearly perfect for frost quakes in our area the last two nights. I heard and felt one at my house last night as well.”

Another commenter, IllSpeaker8551, wrote, “My wife and I have been going crazy trying to figure out what these are. I’ve heard maybe 6-7 in the last 24 hours.”

Frost quakes aren’t strong enough to register on the Richter scale of magnitude used to measure earthquakes produced by the movement of tectonic plates in the Earth’s crust.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.