Chicago has been battling record lows this winter. Last Wednesday, temperatures at Chicago’s O’Hare International Airport dropped to minus 23 degrees, breaking the record set in 1966 of minus 15, HuffPost reported. As a result of the subzero temperatures, the city is experiencing a unique phenomenon known as frost quakes.

According to CNN, residents of Chicago awoke on Wednesday to a loud thundering sound, called a cryoseism or frost quake, which occurs when water underground freezes and swells, causing cracks in the rock and soil of the earth’s surface.


"I thought I was crazy! I was up all night because I kept hearing it," 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."

"What we believe is happening is when there is a significant plunge in the air temperature and the saturated soil cools quickly, the ice in the ground can expand rapidly enough to create a loud boom noise at the surface," geologist Steven Battaglia told the Daily Beast. "Based on the temperature changes in Chicago, it is possible that any areas with saturated ground could have resulted in water expansion and a 'pop' noise near the surface."

According to Battaglia, increasing temperatures from climate change may result in more frost quakes in the future since the warming arctic is generating a smaller temperature gradient between the low latitudes and high latitudes in the Northern Hemisphere, which may be weakening the jet stream. The weaker stream could cause a “wobble” between cold and warm air masses, thereby generating more polar vortexes and more frost quakes. For the time being, frost quakes will most likely be restricted to the flat plains of the Midwest, the southeastern Canada area, and the northeastern U.S. because of the type of soil these areas have.

On Thursday, temperatures dropped below zero again. So far, 11 deaths have now been related to the freezing temperatures. The drop in temperatures has disrupted many services, including mail and transportation with hundreds of flights being delayed or canceled.

The cold in Chicago has also resulted in an increase in hospital admissions. In the past few days, doctors at one area hospital have treated over 50 frostbite victims, several of whom may lose an arm or a leg. "It's a horrific situation," says Dr. Stathis Poulakidas, the head of burn and wound care services at Cook County Health.

Poulakidas, who works at John H. Stroger Jr. Hospital, a level 1 trauma center, says that in extremely cold years, the hospital may treat up to 150 cases of frostbite. So far, this has been one of those years. Many of the victims have been the homeless as well as those who work outside. Poulakidas says they've seen "horrific injuries to feet and hands," which could necessitate amputations. Frostbite in extreme conditions can occur within three to 10 minutes, depending on age, exposure or factors, such as wet gloves and socks, or even alcohol consumption, he says.

Meanwhile, Australia is experiencing a heat wave with one of the warmest winters ever. Temperatures have risen to a record 116 degrees Fahrenheit in South Australia’s capitol, Adelaide. As a result, the nonprofit research organization Berkeley Earth has stated that 2018 was the fourth warmest year on record.

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“The slight decline in 2018 is likely to reflect short-term natural variability, but the overall pattern remains consistent with a long-term trend towards global warming,” the organization said.