Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Climate

It’s Not Your Imagination — We’re Talking About Heat Domes a Lot More These Days

Half of all Americans are sweating under one right now.

A heat dome.
Heatmap Illustration/Getty Images

Like a bomb cyclone, a polar vortex, or an atmospheric river, a heat dome is a meteorological phenomenon that feels, well, a little made up. I hadn’t heard the term before I found myself bottled beneath one in the Pacific Northwest in 2021, where I saw leaves and needles brown on living trees. Ultimately, some 1,400 people died from the extreme heat in British Columbia, Washington, and Oregon that summer weekend.

Since that disaster, there have been a number of other high-profile heat dome events in the United States, including this week, over the Midwest and now Eastern and Southeastern parts of the country. On Monday, roughly 150 million people — about half the nation’s population — faced extreme or major heat risks.

“I think the term ‘heat dome’ was used sparingly in the weather forecasting community from 10 to 30 years ago,” AccuWeather senior meteorologist Brett Anderson told me, speaking with 36 years as a forecaster under his belt. “But over the past 10 years, with global warming becoming much more focused in the public eye, we are seeing ‘heat dome’ being used much more frequently,” he went on. “I think it is a catchy term, and it gets the public’s attention.”

Catching the public’s attention is critical. Heat is the deadliest weather hazard in the U.S., killing more people annually than hurricanes, floods, tornadoes, or extreme cold. “There is a misunderstanding of the risk,” Ashley Ward, the director of the Heat Policy Innovation Hub at Duke University, told me. “A lot of people — particularly working age or younger people — don’t feel like they’re at risk when, in fact, they are.”

While it seems likely that the current heat dome won’t be as deadly as the one in 2021 — not least because the Midwest and Southeastern regions of the country have a much higher usage of air conditioning than the Pacific Northwest — the heat in the eastern half of the country is truly extraordinary. Tampa, Florida reached 100 degrees Fahrenheit on Sunday for the first time in its recorded history. Parts of the Midwest last week, where the heat dome formed before gradually moving eastward, hit a heat index of 128 degrees.

Worst of all, though, have been the accompanying record-breaking overnight temperatures, which Ward told me were the most lethal characteristics of a heat dome. “When there are both high daytime temperatures and persistently high overnight temperatures, those are the most dangerous of circumstances,” Ward said.

Although the widespread usage of the term “heat dome” may be relatively new, the phenomenon itself is not. The phrase describes an area of “unusually strong” high pressure situated in the upper atmosphere, which pockets abnormally warm air over a particular region, Anderson, the forecaster, told me. “These heat domes can be very expansive and can linger for days, and even a full week or longer,” he said.

Anderson added that while he hasn’t seen evidence of an increase in the number of heat domes due to climate change, “we may be seeing more extreme and longer-lasting heat domes” due to the warmer atmosphere. A heat dome in Europe this summer, which closed the Eiffel Tower, tipped temperatures over 115 degrees in parts of Spain, and killed an estimated 2,300 people, has been linked to anthropogenic warming. And research has borne out that the temperatures and duration reached in the 2021 Pacific Northwest heat dome would have been “virtually impossible without human-caused climate change.”

The link between climate change and heat domes is now strong enough to form the basis for a major legal case. Multnomah County, the Oregon municipality that includes Portland, filed a lawsuit in 2023 against 24 named defendants, including oil and gas companies ExxonMobil, Shell, and BP, seeking $50 million in damages and $1.5 billion in future damages for the defendants’ alleged role in the deaths from the 2021 heat dome.

“As we learned in this country when we took on Big Tobacco, this is not an easy step or one I take lightly, but I do believe it’s our best way to fight for our community and protect our future,” Multnomah County Chair Jessica Vega Pederson said in a statement at the time. The case is now in jeopardy following moves by the Trump administration to prevent states, counties, and cities from suing fossil fuel companies for climate damages. (The estate of a 65-year-old woman who died in the heat dome filed a similar wrongful death lawsuit in Seattle’s King County Superior Court against Big Oil.)

Given the likelihood of longer and hotter heat dome events, then, it becomes imperative to educate people about how to stay safe. As Ward mentioned, many people who are at risk of extreme heat might not even know it, such as those taking commonly prescribed medications for anxiety, depression, PTSD, diabetes, and high blood pressure, which interfere with the body’s ability to thermoregulate. “Let’s just say recently you started taking high blood pressure medicine,” Ward said. “Every summer prior, you never had a problem working in your garden or doing your lawn work. You might this year.”

Air conditioning, while life-saving, can also stop working for any number of reasons, from a worn out machine part to a widespread grid failure. Vulnerable community members may also face hurdles in accessing reliable AC. There’s a reason the majority of heat-related deaths happen indoors.

People who struggle to manage their energy costs should prioritize cooling a single space, such as a bedroom, and focus on maintaining a cool core temperature during overnight hours, when the body undergoes most of its recovery. Blotting yourself with a wet towel or washcloth and sitting in front of a fan can help during waking hours, as can visiting a traditional cooling center, or even a grocery store or movie theater.

Health providers also have a role to play, Ward stressed. “They know who has chronic underlying health conditions,” she said. “Normalize asking them about their situation with air conditioning. Normalize asking them, ‘Do you feel like you have a safe place to go that’s cool, that you can get out of this heat?’”

For the current heat dome, at least, the end is in sight: Incoming cool air from Canada will drop temperatures by 10 to 20 degrees in cities like Philadelphia and Washington, D.C., with lows potentially in the 30s by midweek in parts of New York. And while there are still hot days ahead for Florida and the rest of the Southeast, the cold front will reach the region by the end of the week.

But even if this ends up being the last heat dome of the summer, it certainly won’t be in our lifetimes. The heat dome has become inescapable.

You’re out of free articles.

Subscribe today to experience Heatmap’s expert analysis 
of climate change, clean energy, and sustainability.
To continue reading
Create a free account or sign in to unlock more free articles.
or
Please enter an email address
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Bruce Westerman, the Capitol, a data center, and power lines.
Heatmap Illustration/Getty Images

After many months of will-they-won’t-they, it seems that the dream (or nightmare, to some) of getting a permitting reform bill through Congress is squarely back on the table.

“Permitting reform” has become a catch-all term for various ways of taking a machete to the thicket of bureaucracy bogging down infrastructure projects. Comprehensive permitting reform has been tried before but never quite succeeded. Now, a bipartisan group of lawmakers in the House are taking another stab at it with the SPEED Act, which passed the House Natural Resources Committee the week before Thanksgiving. The bill attempts to untangle just one portion of the permitting process — the National Environmental Policy Act, or NEPA.

Keep reading...Show less
Blue
Hotspots

GOP Lawmaker Asks FAA to Rescind Wind Farm Approval

And more on the week’s biggest fights around renewable energy.

The United States.
Heatmap Illustration/Getty Images

1. Benton County, Washington – The Horse Heaven wind farm in Washington State could become the next Lava Ridge — if the Federal Aviation Administration wants to take up the cause.

  • On Monday, Dan Newhouse, Republican congressman of Washington, sent a letter to the FAA asking them to review previous approvals for Horse Heaven, claiming that the project’s development would significantly impede upon air traffic into the third largest airport in the state, which he said is located ten miles from the project site. To make this claim Newhouse relied entirely on the height of the turbines. He did not reference any specific study finding issues.
  • There’s a wee bit of irony here: Horse Heaven – a project proposed by Scout Clean Energy – first set up an agreement to avoid air navigation issues under the first Trump administration. Nevertheless, Newhouse asked the agency to revisit the determination. “There remains a great deal of concern about its impact on safe and reliable air operations,” he wrote. “I believe a rigorous re-examination of the prior determination of no hazard is essential to properly and accurately assess this project’s impact on the community.”
  • The “concern” Newhouse is referencing: a letter sent from residents in his district in eastern Washington whose fight against Horse Heaven I previously chronicled a full year ago for The Fight. In a letter to the FAA in September, which Newhouse endorsed, these residents wrote there were flaws under the first agreement for Horse Heaven that failed to take into account the full height of the turbines.
  • I was first to chronicle the risk of the FAA grounding wind project development at the beginning of the Trump administration. If this cause is taken up by the agency I do believe it will send chills down the spines of other project developers because, up until now, the agency has not been weaponized against the wind industry like the Interior Department or other vectors of the Transportation Department (the FAA is under their purview).
  • When asked for comment, FAA spokesman Steven Kulm told me: “We will respond to the Congressman directly.” Kulm did not respond to an additional request for comment on whether the agency agreed with the claims about Horse Heaven impacting air traffic.

2. Dukes County, Massachusetts – The Trump administration signaled this week it will rescind the approvals for the New England 1 offshore wind project.

Keep reading...Show less
Yellow
Q&A

How Rep. Sean Casten Is Thinking of Permitting Reform

A conversation with the co-chair of the House Sustainable Energy and Environment Coalition

Rep. Sean Casten.
Heatmap Illustration

This week’s conversation is with Rep. Sean Casten, co-chair of the House Sustainable Energy and Environment Coalition – a group of climate hawkish Democratic lawmakers in the U.S. House of Representatives. Casten and another lawmaker, Rep. Mike Levin, recently released the coalition’s priority permitting reform package known as the Cheap Energy Act, which stands in stark contrast to many of the permitting ideas gaining Republican support in Congress today. I reached out to talk about the state of play on permitting, where renewables projects fit on Democrats’ priority list in bipartisan talks, and whether lawmakers will ever address the major barrier we talk about every week here in The Fight: local control. Our chat wound up immensely informative and this is maybe my favorite Q&A I’ve had the liberty to write so far in this newsletter’s history.

The following conversation was lightly edited for clarity.

Keep reading...Show less
Yellow