Wet ground, freezing temps create perfect conditions for frost quakes

Chances of having a white Christmas in central Pa. are slim.

But conditions and the forecast could combine for some holiday frost quakes, said geologist Jeri Jones of Jones Geological Services.

Frost quakes, or cryoseisms, occur when the ground is saturated and mild temperatures quickly drop below freezing. The fast drop in temperatures causes the moisture in the ground to expand when it freezes and that leads to frost quakes, Jones said.

Unlike earthquakes, which can cause severe damage, the worst that can happen with frost quakes is a crack in the ground.

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“There’s no hazard to them,” Jones said Thursday. “They were very common years ago in Canada, Maine, Wisconsin. First time we started to experience them here was about 12 years ago.”

Jones said the first one reported to him came from the Biglerville area. In that instance, the person could see light coming from the crack in their yard, created by the friction and static of the ice expanding.

“He reported a pretty classic frost quake occurrence,” Jones said. “I wouldn’t be surprised to hear something about them tomorrow or tomorrow night.”

Thursday’s temperatures could reach 60 as we usher in Christmas and drop to freezing by noon. Temperatures will continue to drop into Saturday, which will make prime conditions for frost quakes.

How will you know if there has been a frost quake in your area?

Aside from the possibility of an unexpected crack in the yard, a boom could quickly follow the quake.

“If it happens in your front yard or back yard, you or your neighbor might hear it, but that’s about it,” Jones said.

And unless the frost quake happens in close proximity to a seismograph, they aren’t strong enough to register.

Shelly Stallsmith is a trends reporter for the York Daily Record. She can be reached at mstallsmith@ydr.com or followed on Twitter at @ShelStallsmith.