LIMESTONE — The first thought Peter Nicholos had in the early Sunday morning hours was a large tree had fallen across the roof of his River Bend subdivision home in Limestone Township.
It was about 1 a.m.
A quick check turned up nothing of the sort.
About 30 minutes later another boom — somewhat less jarring — grabbed his attention.
He grabbed his flashlight and checked the property. Everything was in order.
“I got back inside and texted some friends and asked if anyone heard this,” he explained.
Replies were returned. They had. Friends from St. Anne and Bradley also heard the noise.
The sharp sound was heard a couple more times during the day.
Miles east in St. Anne Township, Tom Ball was watching late-night television. He was startled by the explosion-like sound.
“It sounded like a 20-pound bowling ball fell through my roof,” Ball said. “Then I thought maybe something happened with my water pipes because it was so cold. I had no idea what was happening, but it was definitely very loud and it sounded like it came from above.”
The large cracking or booming sound was an unusual phenomenon known as a frost quake, an ice quake or a cryoseism.
And these events normally take place between the hours of midnight and dawn, the time Nicholos and Ball were hearing these alarming sounds and began texting one another.
Whatever the name attached to this phenomenon, it is a seismic event caused by a sudden fracturing or cracking of frozen soil or rock which had been recently saturated with water or ice.
If the cracking is strong enough, the process can even cause a shaking motion and a loud boom.
There were other such frost quakes reported not only within Kankakee County, but the northern Illinois region as well.
And while the northern Illinois region is no stranger to a deep freeze, what made this freeze unusual is the fact that it was preceded by what most would term a very mild early winter.
Those two extreme temperature ranges — the mid 40s to 10-to-20 degrees below zero — led to this phenomenon.
<strong>‘IT’S NATURE’</strong>
Max Reams, a retired Olivet Nazarene University geology professor, said conditions were just perfect for frost quakes.
“These are as common as the day is long,” he said. “It’s a common phenomenon in nature. Water seeps down in soil and cracks rocks near the surface and when you get intense freezing, this can happen.”
Reams had doubts the two men heard the same frost quake. He said more than likely this took place in numerous areas.
“What they heard are sounds associated with this rupture,” he said. “It’s nature.”
In a Jan. 18 AccuWeather story, Adam Douty, a senior meteorologist, explained that water expands when it freezes, so it basically pushes apart soil or rocks.
“If this expansion happens all at once, say a rock under pressure gives way and breaks, it can lead to the sound and earthquake-like sensation,” he said.
<strong>NOT AN EARTHQUAKE</strong>
He noted frost quakes or freeze quakes can often be mistaken for earthquakes due to initial indicators appearing similar. Frost quakes, Douty said, have nothing to do with the movement of tectonic plates.
Most often frost quakes occur in the Central and Northern Plains, but any place with saturated soil deep underground and rapidly plummeting frigid temperatures can experience it.
As all attest, the region has been sufficiently watered since mid autumn.
When temperatures are at their freezing point, water deep underground starts to freeze. When temperatures drop quickly, water that has collected freezes solid and immediately begins expanding.
This change cracks the ground around the solid ice formation.
Oddly enough, AccuWeather notes, a blanket of snow, as little as 6 inches, can insulate the ground to prevent a frost quake.
The entire region did not have snow cover.
“It was [expletive] loud,” Nicholos said. “And I had never heard of an ice quake.”
Now he has.