chicago winter 2019
© Teresa Crawford/Associated Press
Chicago’s lakefront is covered with ice on Jan. 30, 2019.
Chicago residents on Jan. 30 reported hearing loud boom-like noises, but there were no earthquakes reported.

WGN-TV reported that the booms might "have been cryoseisms, or frost quakes" amid subzero temperatures.

According to the Maine Department of Agriculture, "A cryoseism, or frost quake, is a natural phenomenon that produces ground shaking and noises similar to an earthquake, but is caused by sudden deep freezing of the ground."

It adds: "They typically occur in the first cold snap of the year when temperatures drop from above freezing to below zero, particularly if there is no snow cover to insulate the ground. The primary way that they are recognized is that, in contrast to an earthquake, the effects of a cryoseism are very localized."

A number of viewers of WGN, based in Chicago, said they could hear them.

"I thought I was crazy! I was up all night because I kept hearing it," viewer Chastity Clark Baker wrote on Facebook. "I was scared and thought it was the furnace. I kept walking through the house. I had everyone's jackets on the table in case we had to run out of here."

Added another: "Yes! I heard one last night. Checked my whole house with a huge knife in my hand!"

Wrote another: "Thank you for reporting this because I was freaking out all night."

The government website says that the vibrations of a cryoseism don't travel very far.

They don't "release much energy compared with a true earthquake caused by dislocation of rock within the earth," the agency says.

According to the agency, "On the other hand, since cryoseisms occur at the ground surface they can cause significant effects right at the site, enough to jar people awake. Cryoseisms typically occur between midnight and dawn, during the coldest part of the night. If conditions are right, they may occur in a series of booms and shakes over a few hours or even on successive nights."

Polar Vortex

Temperatures in Chicago got to minus 20 at night, according to forecasters.

One of the coldest arctic air mass intrusions in recent memory is surging south into the Upper Midwest before spreading across much of the eastern two-thirds of the country," said the National Weather Service.

Wind chill warnings were in effect for much of the Midwest.
polar vortex US 2019
© National Weather Service
Amid the so-called “polar vortex” that’s affecting the Midwest, some have noted that Chicago will be colder than Antarctica the week of January 30, 2019
"Through late week, expect frigid temperatures, bitterly cold and life-threatening wind chills, likely leading to widespread record lows and low maximum temperatures from the Upper Midwest to the Great Lakes and Ohio Valley," the NWS stated on its website.

"The heart of this cold... is hitting us now. A lot of records are going to fall," said Brian Hurley, a meteorologist with the NWS's Weather Prediction Center in Maryland, Reuters reported.
Wisconsin winter 2019
© Jeffrey Phelps/Associated Press
The sun rises behind icicles formed on the harbor in Port Washington, Wis., on Jan. 30, 2019. A deadly arctic deep freeze enveloped the Midwest with record-breaking temperatures.
With officials in Illinois and the Northern states advising residents to stay indoors, dashcam footage from one trucker taken outside Grand Rapids, Michigan gave a snapshot of hair-raising driving conditions.

"I about just got caught in a giant wreck; cars are into other pickups, there's people hurt. I gotta let you go." Jason Coffelt is heard saying in an Instagram posting dated Tuesday, as his truck is forced off the highway and pulls up just before a multi-vehicle accident. In neighboring Illinois, Chicago was bracing for one of its coldest days on record.

Reuters contributed to this report
Jack Phillips is a reporter at The Epoch Times.