Researchers predict a combined heatwave and blackout in Detroit could be worse than Katrina. Here’s why.

A street light near Michelle Jones’ house in Highland Park. Photo by Nick Hagen.

Last July as strong storms moved through metro Detroit, Highland Park resident Michelle Jones lost power for three days.  At the same time, the area was experiencing 90-degree temperatures. Since Jones couldn’t run her window air conditioner or fans, she went to stay with her daughter. 

Two days later she came home expecting the power to be reconnected, based on an estimate she received from DTE Energy. Yet, when she got back, her power was still out.

“The thermostat and the thermometer in the house never went below 87 degrees,” Jones said. “It was just suffocating; you couldn’t breathe.”

Jones worries what another combined heatwave and power outage could mean this summer, especially for the city’s many older residents who are at the greatest risk during a heat event. She mentioned a nearby apartment building that lost power during last year’s blackout, and wonders how the mostly older residents there would be able to get help if this happened again.

“So, am I nervous about this summer?” she said. “Yeah, a little bit.”

Jones’ concerns are well-founded. A new study in the journal Environmental Science & Technology shows that Detroit is in serious danger from a simultaneous heatwave and power outage. And this danger is increasing because of climate change and more frequent blackouts that can last for days. 

Moreover, Detroiters may be in significant danger even if there isn’t a power outage, on account of so many residents lacking air conditioning, the type and quality of housing, and a high level of underlying health issues. And city-run cooling centers can only serve a fraction of the city’s population, and generally lack backup power.

Preventing a heatwave disaster in the city will require a radical rethinking of how cooling centers operate, along with things like housing retrofits and energy assistance to help residents stay cool in their homes.

“If you have a historical heatwave and a blackout, and it persists for as long as five days, you’re very likely going to see many more fatalities than we saw in New Orleans after Katrina,” said Brian Stone Jr., a professor at the Georgia Institute of Technology’s School of City and Regional Planning and the lead author of the study that looked at the impact from concurrent blackouts and heatwaves in Detroit, Atlanta, and Phoenix.

Stone was speaking specifically of Detroit when he referred to Hurricane Katrina, which killed an estimated 1,464 people in New Orleans before and after the storm. And he emphasizes that his team’s modeling of heatwave impacts were based on an actual  “historical heatwave” — specifically the 1994 Detroit heat event where temperatures stayed above 90 degrees for seven days — and not the more extreme heat scenario that the experts say the city can expect with climate change. Across the United States, heat already causes an estimated 12,000 fatalities a year. This number could increase dramatically with global heating.

“Every dimension of heatwaves has been increasing over the last 20 years,” Stone said. This means that heat events have increased in number, intensity, and duration, and they’re starting earlier in the year.

The report also found that since 2015, the annual number of blackouts has more than doubled across the country and that a disproportionate number of them are happening during the summer months, which could make the risk of a concurrent heatwave and blackout more likely.

Nationally, hurricanes and wildfires contribute to a high number of blackouts in summer. And Michigan isn’t immune to these problems. Last summer, tropical cyclone Cristobal passed over Lake Superior, the first such storm ever recorded doing so, causing more than 55,000 power outages in the state. 

When hot weather drives more people to use air conditioning, the higher energy demand can cause overhead wires to heat up and sag, hitting trees or other vegetation and shorting out. In 2003, sagging wires helped cause the blackout that knocked out power in much of the eastern U.S. and Canada.

Detroit may also be especially vulnerable to power failures. Michigan ranks fourth nationally for the number of hours each year that the average customer is without power. Users experience about 8.5 hours of outages annually compared to a national average of 4.5. According to a report from the Citizens Utility Board of Michigan, DTE Energy customers in Detroit experienced particularly long outages.

In 2018, it took the utility 358 minutes or six hours to restore power, the longest of any investor-owned utility in the state. DTE spokesperson Je’well Pearson said the company is, “investing nearly $1 billion on behalf of our customers to upgrade the grid each year and improve reliability”. This includes money for things like tree trimming, inspecting overhead power lines, and upgrading substations.  

Yet, Stone says that Detroit is at elevated risk during heatwaves even if there isn’t a power outage. The study found 50,000 residents are at risk of health impacts like heat exhaustion or heat stroke without a blackout on account of factors like a lack of air conditioning and a large number of single-family homes. That number increases to 450,000 — roughly two-thirds of the city’s population — when there’s a simultaneous blackout and heat event.

The heatwave study also found that 47% of Detroit homes had no access to air conditioning or only partial access, i.e. window units. And more than 60 percent of Detroit’s housing consists of single-family homes, many of them older and lacking good insulation that can keep heat out. In contrast, apartment buildings or other multi-unit dwellings mitigate against extreme temperatures because their larger thermal mass is better able to distribute heat.

These vulnerabilities in Detroit’s housing stock and energy reliability could compound warming trends in increasingly dangerous ways. The Great Lakes Integrative Science Assessments’ (GLISA) Detroit study from 2013 showed that annual temperatures in the years between 1981 and 2010 were 1.4 F higher than the period from 1961 to 1980. Most of this change came from increases in overnight temperatures, which went up 4.3 F.

This is concerning because an inability to cool down overnight presents the greatest risk for severe illness or death during a heatwave. In Detroit, GLISA predicted 255 deaths a year from extreme heat for the period between 2020 and 2029, increasing to 701 fatalities annually by the end of the century.

How to protect residents in Detroit’s neighborhoods

Jones’ neighborhood in Highland Park has many older houses that lack central air conditioning and aren’t energy efficient. But she says the biggest roadblocks to staying cool in the summer are power outages and paying expensive electric bills that can lead to shutoffs.  

During an outage, Jones points out that those with health problems or disabilities may not be able to charge electric wheelchairs, use breathing machines or keep insulin cool. And heat itself can magnify health problems. The GLISA report mentions that the increased production of ground-level ozone at higher temperatures could trigger asthma attacks. 

Carina Gronlund, an environmental epidemiologist at the University of Michigan’s Institute for Social Research, says that heat can also be especially harmful to people with heart conditions and cognitive disabilities like dementia or Alzheimer’s disease. And according to 2017 data from the Michigan Department of Health and Human Services, Detroiters are much more likely to report health problems, with 30.1 percent of Detroiters responding that their health is “fair or poor” compared to the state average of 18.1 percent.

Access to cooling centers may help protect some people with underlying health conditions, but a concurrent power outage would complicate matters because Detroit doesn’t require cooling centers to have backup power. The city of Detroit did not respond to a request for comment for this article, however Christopher Kopicko, a spokesman for the Detroit Office of Homeland Security & Emergency Management, recently said that one of the city’s 11 cooling centers had backup power and that mobile generators would be available to power some of the other sites. He added that certain large venues in the city agreed to serve as cooling sites and that residents could also go to any of Detroit’s 12 police precincts, which all have backup power.

Some have pointed out the problem with potentially asking residents of a majority African American city to go to police stations for cooling after years of high-profile incidents of police violence directed at Black people. Eric Klinenberg, director of New York University’s Institute for Public Knowledge and author of the book “Heat Wave” — which covers the 1995 Chicago heatwave that caused more than 700 fatalities — previously said, “If this is Detroit’s plan, what that tells me is Detroit is not planning.”

Although Jones sees cooling centers as an important option, she wonders if people will really want to spend that much time in one of these facilities over a multi-day heatwave. And despite declining case numbers in Michigan, she says that COVID is still likely to deter people from using cooling centers this summer.

The high cost of utilities can also keep people from using air conditioning at home even if they have it. 

“You’ve got to realize sometimes it’s the difference between buying a loaf of bread and paying your bill to DTE,” said Dr. Jalonne L. White-Newsome, CEO and Founder of Empowering A Green Environment and Economy, LLC, an environmental consulting firm. Her research in Detroit shows that older residents were often reluctant to turn their air conditioning on or that their homes didn’t get that much cooler when they used it. She added that concerns about safety can also keep people from opening their windows to cool down.

“Heat has always been one of those invisible threats that people don’t get until something happens,” White-Newsome said. And this inability to perceive the threat from heatwaves may extend to public health officials themselves. A recent survey of Michigan Public Health Departments found that only 35 percent of public health officials believed that climate change was a public health priority for their departments.

Still, White-Newsome says that health departments are crucial for responding to climate change and that heat awareness and education could be combined with COVID outreach. She emphasizes that this information needs to be disseminated to hospitals, doctors, and health care clinics, so that heat can be properly managed as the threat that it is. 

“There needs to be a massive education campaign because the interventions are layered,” she said. “It’s not just making sure that there’s green space in front of someone’s house, it’s also the medications that people prescribe to our seniors, it’s also the ways in which we behave.”

What this might look like at the neighborhood level are strategies like tree planting â€” which can make areas with a good canopy as much as 20 degrees cooler than those lacking trees, retrofitting homes so they can be more efficiently cooled, and the creation of resilience hubs where residents feel safe going not only to cool down, but also to access a broad array of services.

“They can move beyond this kind of cooling center idea and really think about what place-based locations can really serve a multitude of needs as we deal with the climate crisis,” said Tony G. Reames, an assistant professor at the University of Michigan’s School for Environment and Sustainability.  Detroit’s Eastside Community Network is planning on opening one such hub in 2021 where they will offer things like food, internet access, recreational activities, and health care. Crucially, this facility will also have backup power from solar panels and battery storage.  

But whether it’s cooling centers or resilience hubs, Detroit likely needs a number of these spaces to make up for the lack of air conditioning and the city’s large geographic footprint. Stone and the  other researchers found that right now Detroit only has enough cooling centers to accommodate 1-2 percent of its population.

Reames emphasizes that more affordable power would be crucial for helping people stay cool at home, which could involve capping utility bills at 6 percent of a household’s income and supplementing these payments with assistance from government programs like Michigan’s Low Income Home Energy Assistance Program.

Burying power lines and building more distributed, renewable generation sources and battery storage could also help avoid the blackouts caused by failures at large power plants or downed power lines. “It’s a combination of energy affordability, energy efficiency, and renewable energy,” Reames said.

In the meantime, Jones is working with the Highland Park nonprofit Soulardarity to hand out resilience kits that include 30 days’ worth of staple foods, solar-powered lights, solar-powered phone chargers, and insulated bags with ice packs to keep food cold. These kits may help residents during the next power outage, but may not provide much relief if it coincides with a heatwave.

Stone says he’s optimistic that the Biden administration can find the money for things like housing retrofits through a proposed infrastructure bill that could target places like Detroit, where there is a dire need for help with home repairs. The city of Detroit also announced that it will spend $20 million of the roughly $800 million it’s receiving in COVID relief to help seniors and low-income families with home repair.

However, Stone is far from sanguine about what is at stake, saying the extreme cold that hit Texas this past winter was a demonstration of what happens when blackouts coincide with extreme weather. More than a hundred people died from things like hypothermia and medical equipment failures during that disaster, although the real number of deaths may be much higher.  

“We saw the winter versions play out in Texas,” he said. “I think that was absolutely a wake-up call.”

This report was made possible in part by the Fund for Environmental Journalism of the Society of Environmental Journalists. SEJ credits its foundation partners and other donors for supporting this project.