The program aims to help cities map urban heat islands


Even in the dead of winter in North Carolina, Tobin Freid, Durham County’s sustainability officer, ponders the potential impacts of the heat.

“One of the main impacts that we’re seeing and expecting to see more of is extreme heat events, so either very high temperatures or very prolonged periods of high heat levels,” Freid said.

“In an area like this it can be up to 20 degrees warmer than an area a mile and a half away which has more green space, more trees. So on hot days it’s even hotter in those areas,” she said, referring to urban areas filled with buildings, parking lots and asphalt.

Durham and Raleigh, which are neighboring cities, take a closer look at urban heat islands.

“Green spaces stay a little cooler, and places with lots of sidewalks and buildings heat up a lot faster, so we’re calling these urban heat islands,” said North Carolina State climatologist Kathie Dello at NC State University.

“Things around these things like brick and asphalt and concrete are going to feel warmer, longer,” Freid said.

The question is, how much hotter?

Raleigh and Durham were one of several dozen regions to receive a grant in 2021 for the CAPA Heat Watch program, a nationwide program that examines heat on a granular scale. The program is delivered through a partnership between the National Integrated Heat and Health Information System and CAPA Strategies.

“What we wanted to do was get the temperature reading of where humans feel heat on their skin and we wanted to do that at a very high resolution,” said Vivek Shandas, advisor at CAPA Strategies .

“In the case of Raleigh-Durham, we collected almost 100,000 metrics on a warm, fairly hot day on July 23, 2021. So those 100,000 metrics, compare that to the single metric you get for a whole city,” he said.

Over the summer, volunteers like Jenna Gant helped collect the data. Volunteers drove, cycled and walked with these sensors to collect information.

“You have the temperature sensor that you put on the window, then you roll up the window to put it in place, and once it starts collecting data, you have your route,” Gant said.

“There are sensors that map heat and relative humidity every 15 seconds,” Freid explained. “Right after the campaign, we packed up all the sensors and sent them back to NOAA for analysis. They extracted all the data from it.

She received the results at the end of 2021. This is an annual process that has been going on for years. Cities such as San Diego, Detroit, and Miami have all applied, been accepted, and received grants for the Heat Watch program in the past. They received the data in the form of heatmaps in return.

“We want to introduce them to planners, public health officials,” Shandas said.

Heat is the deadliest climate hazard in the United States. It contributes to about 143 deaths per year, according to NOAA.

“Extreme heat poses a very big public health risk, both daytime heat and nighttime heat. And we know where people live isn’t fair, so a lot of low-income people live in places without adequate shade and access to green space,” Dello said.

“We wanted to make sure that we’re covering particular neighborhoods that have a history of racism, that have pockets of poverty, as well as more affluent neighborhoods so that we can kind of compare the impacts of heat in those different areas,” said Freid.

She said the city recognizes that historical and institutional racism resulted in the effects of extreme heat affecting some parts of the community more than others.

Freid said this data can help form better solutions ranging from more trees to better cooling options in different neighborhoods, which they will engage with the community moving forward.

“It will not be something that will be fixed tomorrow. It’s something that’s going to take some time to put these things in place,” she said.


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