The loud booms that many people across the Upper Cumberland have heard over the past couple of days are not earthquakes but what meteorologists call frost quakes.
Local meteorologist Michael Detwiler said a cryoseism, also known as a frost quake, happens when the ground is saturated with water and then quickly freezes and expands due to a rapid drop in temperature. This causes soil and rocks to crack, producing a loud sound. Detwiler said frost quakes are very rare in our region.
“As I tell people to bake that cake properly, you have to have all the ingredients, and so the frost quake is very similar in that we need all of the ingredients,” Detwiler said. “The big one is the rapid drop in temperature.”
Detwiler said frost quakes can sound like something falling on a roof or a shotgun going off. He added that because frost quakes are so rare, people in the region have often mistaken the loud sounds.
“As I dug into it more, I found out the Overton County 911 folks have been receiving calls about this sound, and that’s when it was determined to be the actual frost quake,” Detwiler said.
Detwiler said frost quakes usually occur late at night or before dawn. However, reports this week began in the early evening on Monday. He said the reports are a testament to how cold it has been across the region.
“Let’s just go back to less than a week ago, we had highs in the 50s, but obviously, the last several days we dropped off the cliff,” Detwiler said. “The day before yesterday, with a low of 15, and then yesterday, we struggled and only got up to 16 after a morning low of eight, and then of course started out at eight degrees and have risen nicely.”
Detwiler said frost quakes are not dangerous, other than producing a loud sound. He encouraged people to keep an eye on the weather forecast this week, as frigid temperatures continue with a chance of snow this weekend.