Last month, record-breaking heat overwhelmed the eastern United States, triggering emergency power situations across the region. This intense heat was caused by a weather pattern known as a heat dome—a large area of high pressure that traps warm air beneath it, creating scorching temperatures. The same phenomenon has already hit parts of Europe and China this summer, leading to the temporary closure of landmarks like the Eiffel Tower and damaging important crops such as rice.
Heat domes happen when a strong high-pressure system settles over a region, holding in heat and blocking cooler air. This effect can last for days or even weeks, intensifying the heat under it. Meteorologists use the term “heat dome” to help people understand the threat of extreme heat, which is far more dangerous than typical summer warmth. As Scott Handel, lead forecaster at the US Climate Prediction Center, pointed out, record-breaking heat can pose serious risks to health and safety.
Extreme heat doesn’t just affect people’s comfort—it has a big impact on daily life and the economy. Prolonged heat waves raise the demand for electricity, push up energy prices, and make it harder for transportation systems like airplanes and trains to operate efficiently. Wildfires and droughts often follow, causing billions of dollars in damage and many deaths. In the US, wildfires between 1980 and 2024 caused nearly $148 billion in property losses and claimed over 500 lives. Droughts during the same period inflicted even greater financial damage—more than $367 billion—and caused thousands of deaths.
Heat-related fatalities are a serious issue. From 1979 to 2022, over 14,000 Americans died due to heat-related causes, according to the US Environmental Protection Agency. One recent study even estimated that more than 61,000 people died from heat in the summer of 2022 alone.
Scientists are trying to better predict these heat domes, but they remain tough to forecast. Unlike other weather events such as cold air outbreaks or El Niño, which can be predicted weeks or months ahead, heat domes often give only a short warning. Meteorologists track changes in the jet stream—a powerful, fast-moving air current circling the globe—to help anticipate these events. A key measure they watch is called the Global Atmospheric Angular Momentum (GLAAM). When this metric is low, it can signal that a heat dome and widespread high temperatures may be on the way.
Climate change is making heat domes more common and intense. The planet is warming, especially in the Arctic, which changes weather patterns and the jet stream’s behavior. This can cause heat domes to stall in one place longer, trapping hot air. However, researchers are still studying exactly how Arctic warming affects the jet stream, with some findings showing mixed results.
Even small temperature rises during the hottest days can make summers feel much more extreme and dangerous, experts say. That’s why improving heat dome forecasts is so important to help communities prepare and respond.
As the world continues to warm, heat waves driven by these domes will likely become more frequent and severe, underscoring the urgent need to understand and tackle the risks associated with extreme heat.