Blistering heat dome smothers US: ‘Corn Sweat’ and climate change drive Midwest into triple-digit chaos?
HeatRisk forecast for July 27, 2025 Photograph: (National Weather Service)
A major heat dome is lingering over the eastern part of the US, which will be affecting at least 90 million people with miserable heat, followed by instances of thunderstorms and flash floods. Know all about the heat dome, which cities to be affected and why it is a recurring phenomenon.
A heat dome is swirling over the eastern part of the US, warned meteorologists. More than 70 million people are at risk of facing intense heat and potential record-breaking temperatures. According to the forecast by the National Weather Service, a branch of the National Oceanic and Atmospheric Administration, the number of people affected will be 90 million by July 25.. The meteorological department has attributed the miserable heat condition to a phenomenon called the heat dome.
What is a heat dome?
A heat dome is a weather pattern when a high-pressure system traps hot air in a place, like a lid on a pot. This causes the temperature to increase drastically while suppressing cloud formation and heat. Thus leading to an intense period of heat and humidity. The current period of heat is estimated over the Midwest and Southeast United States at 115°F or higher in some cities.
Which US cities are affected by the current heat dome?
According to the Heat Advisory, more than 160 million Americans are at risk of excessive heat. The most intense being Illinois, Iowa, Missouri, Indiana, Arkansas, Mississippi, Tennessee, Kentucky, Georgia, Alabama, the Carolinas, and Virginia. The southeast region is at most risk with the heat dome centred over Memphis, Tennessee. Cities like Baltimore and Inn Harbour have already faced their highest temperature for the month, St. Louis, Chicago, Memphis, Des Moines, and Louisville are recording in the range of 105-115 degrees.
In the corn belt areas with huge corn fields are releasing massive amounts of water which are creating a humid room of steam known as ‘corn sweat’, raising the heat index outside of the thermometer's measurement.
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How long will the extreme heat last in the eastern US?
According to meteorologists, this is likely to last till the end of July. The temperature will remain dangerously high across the Southwest and the Midwest. There is another disturbing pattern around the border of the heat dome, also known as the ring of fire. Moist air at the perimeter of the ring of fire is creating thunderstorms and flash floods, especially in Appalachia, the Ohio Valley, and parts of the Southeast.
Is global warming behind the frequent heat domes in the US?
According to Climate Central’s Climate Shift Index, human-induced climate change has made the occurrence of the dome 3-5 times more likely. What is more disturbing is the trend of 'wet heat', which is heat with humidity, as it is particularly disturbing for the body's cooling mechanism. These increased frequency and intensity of heat waves are most likely to lead to infrastructure strain, such as energy grids and transportation systems, as well as increase the risk of heat-related illness among the public.
