Major cities across the United States are preparing for extreme temperatures caused by a heat dome that hit the U.S. Plains on Friday and is expected to expand to much of the rest of the country over the coming days.
Potentially dangerous temperatures of 105 degrees Fahrenheit (40 Celsius) or over are expected this weekend in parts of the Midwest, including Chicago, before spreading to the Ohio Valley and much of the East Coast towards the start of next week, according to the National Weather Service.
A heat dome is a ridge of high-pressure air in the upper atmosphere that stalls and traps hot air while keeping cooler air away even at night.
In preparation, Chicago is opening cooling centers across the city, Mayor Brandon Johnson told a news conference on Friday. City workers are also checking on people who are homeless living in camps, urging them to go to a cooling center.
"Chicago knows better than any other city in America of the danger of extreme weather, particularly extreme heat," said Johnson, referring to the upcoming 30-year anniversary of a heat wave that killed 700 Chicagoans.
New York City Mayor Eric Adams urged residents to locate their nearest cooling center. Adams said the city would open up an extensive network of cooling centers and was working to distribute heat safety information to vulnerable residents.
Heat affects health in several ways. Heat exhaustion, which can include dizziness, headaches, shaking and thirst, can affect anyone, and is not usually serious, providing the person cools down within 30 minutes.
The more serious version is heatstroke, when the body's core temperature goes above 105 degrees Fahrenheit (40.6 degrees Celsius). It is a medical emergency and can lead to long-term organ damage and death. Symptoms include rapid breathing, confusion or seizures, and nausea.
Heat advisories were already in effect across cities in Colorado, Nebraska and Kansas on Friday, with temperatures in Denver, Colorado, expected to rise to 100 degrees Fahrenheit by 3 p.m.
Some of the highest temperatures on Friday are expected in towns close to the Nebraska-Kansas border, with those in Kansas's St. Francis and Oberlin, and McCook, Nebraska, likely to rise to 105 degrees and over before the end of the day, according to the National Weather Service.
Forecasters say it is difficult to link record-breaking heat experienced across the United States in recent years to human-induced climate change, but such extremes are becoming more frequent because of global warming.
