The upper midwest is bracing for some dangerously cold weather this week. Wind chills are expected to reach levels not seen since the 1990s in parts of Illinois, Minnesota, Iowa, Wisconsin and the Dakotas, the National Weather Service predicted.

Temperatures will dip 20 to 40 degrees below average Tuesday through Thursday, and wind chill temperatures could hit -60 degrees in the upper Midwest and -55 in the upper Mississippi Valley, U.S. News and World Report reported.

"You're talking about frostbite and hypothermia issues very quickly, like in a matter of minutes, maybe seconds," NWS Weather Prediction Center meteorologist Brian Hurley told The Associated Press.

The Chicago NWS said the forecast was for "life-threatening extreme cold," The Washington Post's Capital Weather Gang reported. The dangerous cold snap could potentially break records, with forecasts for Chicago, Des Moines, Cleveland, Detroit and Minneapolis putting temperatures within one degree of the coldest ever recorded. In Chicago, some forecasts on Monday put temperatures at -29 degrees, two degrees below the lowest on the books.



Minneapolis Public Schools are closing through Wednesday to protect students, as are some schools in eastern Iowa, and the Chicago Public School system is keeping an eye on the thermometer, The Associated Press reported. Homeless shelters are also gearing up for the onslaught. Organizations in Minneapolis are working to increase hours and beds.

"The charitable organizations responsible for operating shelters are adding emergency capacity as they do whenever dangerous extreme temperature events occur," Hennepin County emergency management director Eric Waage told The Associated Press.

The Washington Post's Capital Weather Gang explained why cold weather is so dangerous:

"A recent report from the Centers for Disease Control and Prevention found that cold weather is responsible for the majority of weather-related fatalities. The wind chill temperature is more than a catchy forecast term. The wind blows away the insulating layer of warm air around us generated naturally by our bodies. Wind chill attempts to quantify the effect in terms of how it feels on our skin, which is why you'll sometimes hear it called the "feels like" temperature. A wind chill of minus-20 degrees can cause frostbite in as little as 30 minutes."

The freezing temperatures are caused by something called a polar vortex, an area of low pressure and cold air that circulates around the poles. As warm air from Morocco entered the Arctic last month and caused it to warm about 125 degrees, this influx of warm air divided the polar vortex, sending one of its pieces down to freeze the Midwest, atmospheric environmental research expert Judah Cohen told The Associated Press.

Some scientists also think that climate change is making the polar vortex increasingly unstable, as warmer temperatures in the Arctic cause the jet stream to push more cold air further south, National Geographic explained.

Despite this, President Donald Trump once again used the predicted cold snap as an excuse to deny climate science.



"In the beautiful Midwest, windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. In coming days, expected to get even colder. People can't last outside even for minutes. What the hell is going on with Global Waming? Please come back fast, we need you!" he tweeted.

This prompted journalists to repeat the truth that climate and weather are not the same thing.



"The globe as a whole is still much warmer than normal, and scientists say the cold snap in parts of the U.S. in no way invalidates the overwhelming scientific evidence showing global average temperatures are increasing due to the burning of fossil fuels for energy," Axios' Andrew Freedman wrote.

Correction: An earlier version of this story said that temperatures could hit -60 degrees in the upper Midwest and -55 in the upper Mississippi Valley. The story has been updated to specify that those are wind chill temperatures.