Cedar Rapids, Iowa City urban cores more susceptible to dangerous heat, research finds

The urban cores in Cedar Rapids and Iowa City are more susceptible to dangerous heat pockets than surrounding areas, according to results from a community science campaign within a National Oceanic and Atmospheric Administration project.

Extreme heat has reigned as the No. 1 weather-related cause of death in the U.S. for the last three decades. This burden disproportionately impacts certain populations — older adults, homeless people, inmates and low-income communities — making it an environmental justice issue.

That’s why NOAA is partnering with communities across the country to investigate urban heat islands. Those are urban areas that get substantially hotter — up to a 20 degree difference — than surrounding areas due to their human-made infrastructure that absorbs and radiates heat.

The Cedar Rapids and Iowa City region was one of 18 areas in 14 states and one international city that took part in this year’s NOAA campaign, dubbed “Spot the Hot” in the Corridor.

“I really can't emphasize enough that this is the highest death-related weather event, and we want to prevent those,” said Sara Maples, the Cedar Rapids Sustainability Program Manager who helped coordinate the campaign, about extreme heat. “We want our residents to be able to prepare for that. The key thing is building awareness and then making sure residents know what they can do to stay safe."

July 2023 marked the hottest month in the global temperature record dating back to 1880, according to NASA.

On July 22, 86 volunteers braved temperatures up to 90 degrees to map temperature variations across Cedar Rapids and Iowa City. In the morning, afternoon and evening, they drove sensor equipment throughout 14 routes over 100 square miles.

Altogether, they collected nearly 84,000 temperature and humidity measurements that were used to construct heat maps — creating a snapshot of how heat is distributed across different communities.

The highest and lowest temperatures recorded on July 22 spanned a 14.4 degree difference. Heat peaked between 3 p.m. and 4 p.m., especially in the downtown cores of Cedar Rapids and Iowa City.

The areas lining First Avenue in Cedar Rapids, for example, experienced some of the highest temperatures, as well as the developments between Collins Road and Blairs Ferry Road. In downtown Iowa City, parking lots and buildings around the Pedestrian Mall radiated heat throughout the day, and hot spots trailed along Gilbert Street.

Parks and natural areas, on the other hand, were considerably cooler. Cedar Rapids’ Flaherty Park, Irene Dumpke Park and Van Vechten Park experienced lower temperatures than their surrounding areas, along with Hickory Hill Park and Sycamore Greenway in Iowa City.

The Cedar Rapids areas subjected to the most heat closely align to areas identified as disadvantaged through the Biden Administration’s Climate and Economic Justice Screening Tool, Maples said.

Almost all of the census tracts around downtown Cedar Rapids — which light up hot red on the temperature maps — rank above the 65th percentile nationally for the amount of low-income households.

“We know that people in these areas already are going to be more vulnerable” to heat, Maples said. “It's a matter of thinking about how we can then use this information to inform different strategies in the future.”

The best way to address the heat inequity in the cities is through tree planting, she continued. ReLeaf Cedar Rapids relied on satellite data to plan its tree replanting strategy; the new localized data could tailor planting efforts even more for the areas that need them most.

It could also inform the cities where to add shade structures, water fountains or green or cool roofs, or how to alter public transportation routes to be more equitable.

“It really is a matter of, I think, how can we best keep our residents safe,” Maples said, “and also bring awareness to the fact that we do need to be addressing heat and making that part of the conversation.”

Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; brittney.miller@thegazette.com