A Heat Dome Is Crushing the Heart of the US. Here's Why

Understanding the Heat Dome Phenomenon

You've likely heard of the heat index and might be familiar with the National Weather Service's HeatRisk tool, but have you ever wondered what a heat dome is? If not, now is the perfect time to learn. Nearly a third of the United States is set to experience temperatures above 100 degrees due to an ongoing heat dome.

The National Weather Service has issued a bulletin warning that 100-degree temperatures will likely impact residents in the central part of the country today. This temperature spike is caused by a growing heat dome in the Mississippi Valley, which is expected to expand toward the northeast by the end of the week. According to Accuweather, this could affect over 100 million people.

If "heat dome" is a new term for you, keep reading as we break down what it means and how it forms. For additional help this summer, explore DISCOVER TREND’s top 10 hacks for keeping your home cool or learn how to recognize the early signs of heatstroke.

What Exactly Is a Heat Dome?

Think of a heat dome like placing a lid on a pot while cooking. Alex Lamers from the National Weather Service explained this analogy to NPR. A heat dome occurs when a high-pressure system lingers, trapping hot air underneath it and causing prolonged temperature increases. Just like a lid traps heat to cook food faster, a heat dome traps heat, affecting people and environments.

High-pressure systems are also known for creating dry weather, which can further intensify heat. According to the heat map from the National Integrated Heat Health Information System, elevated heat risks are present across much of the country, particularly in the Midwest, Lower Mississippi Valley, and East Coast regions. Areas such as eastern North Carolina, central Virginia, the Pittsburgh area, southeast Pennsylvania, southeast Maryland, most of New Jersey, and nearly all of Delaware are under extreme heat warnings.

In the most affected regions, temperatures could reach up to 115 degrees, while other areas may see temperatures between 95 and 100 degrees. Such weather conditions can turn the possibility of a power outage into a life-or-death situation.

How Long Do Heat Domes Last?

Unfortunately, there isn’t much good news about the duration of heat domes. They can last anywhere from a few days to several weeks, depending on how long the high-pressure system remains in place. There is currently no clear indication of how long the current heat dome will persist.

Accuweather reports that the heat dome could even spread to the western US in early August. This highlights the potential for widespread and prolonged heat events across the country.

The Role of Climate Change in Heat Domes

Climate change is making heat domes more severe. Speaking to Time Magazine about the current heat wave, Bill Gallus, a professor of meteorology at Iowa State University, stated that the link between climate change and heat domes is one of the easier questions to answer.

Gallus explained that heat domes are among the more likely consequences of worsening climate change, surpassing other related weather events like increased tornadoes or stronger hurricanes. “There are many things that are complicated and we can't say for sure what climate change will do, such as how many hurricanes or tornadoes we get,” Gallus said. “But it is likely that we will have more heat domes and probably hotter temperatures within those heat domes.”

How to Stay Safe During a Heat Dome

As you might expect, the best way to avoid the effects of a heat dome is to stay away from it. This could mean staying indoors where it's cooler or traveling to a different region not experiencing the high-pressure system. Perhaps heading to the West Coast, where colleagues suggest the weather is quite temperate, could be a good option.

Alternatively, you could try the classic summer activity of watching a movie in an air-conditioned theater. DISCOVER TREND’s Aaron Pruner describes Superman as a “punk rock delight,” and the new F1 movie looks promising too.

For more tips on managing power during summer heat waves, check out DISCOVER TREND’s guide to saving energy during extreme heat.