Kentuckians reported loud pops during winter storm — they were rare frost quakes
Those loud booms or pops you heard during Winter Storm Fern? They’re not fireworks being set off, but frozen water bursting underground.
The weather phenomenon, which is rare in the South and has been reported across Kentucky over the weekend during, is known as a frost quake or cryoseism. The pops occurred sporadically going into Tuesday morning after this weekend’s winter storm brought snow, sleet and rain to the commonwealth.
“It’s kind of like the same idea of why pipes burst,” National Weather Service meteorologist Brian Neudorff said.
The weekend’s precipitation, having seeped into the ground, froze rapidly as temperatures plummeted. Water expands as it freezes, building pressure, and at a certain point, it has nowhere to go but out.
“This is already a rare event, and for it to happen in Kentucky is even rarer,” Neudorff said. “And again, it’s just a situation where all of these conditions have to be met.”
The conditions include having temperatures warm enough to not allow precipitation to freeze before getting into the ground. Then, Neudorff said, temperatures must drop over the course of about “16 hours to 48 hours” to well below freezing.
Such dramatic swings in temperature are more common in the Midwest, AccuWeather meteorologist Tom Kines said.
“Usually when you get these Arctic air masses coming down, and if there’s snow cover up,” the conditions for cryoseisms may present themselves, Kines said. Kentucky doesn’t usually see those conditions, and Neudorff said he hadn’t heard of them in his six years working in Louisville’s NWS office.
The areas of Kentucky that received the most reports of cryoseisms also saw the most ice and rain as a result of the storm, Neudorff said. The pops occur a few feet underground.
Kentuckians are unlikely to experience more frost quakes in the near future as temperatures stay well below freezing.
“This was probably our coldest morning that we’re going to see,” Neudorff said Tuesday. While it’s “possible” more cryoseisms could occur, they are likely to be “very isolated.”
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