Homes and businesses up and down Interstate 35, the Gardner-Edgerton area and western Olathe suffered more from the heat and humidity last summer than other parts of Johnson County, according to the results of a heat mapping study done in August.
Another particularly hot spot in the area was across the county line in Wyandotte County at rail yards and an industrial area near Armourdale and Argentine, according to the study.
Trained volunteers gathered heat data last summer
The heat mapping study was the first of its kind for Johnson County and Wyandotte County and is intended to give county and city officials an idea of where the worst heat islands are.
It was part of an ongoing effort by the National Oceanic and Atmospheric Administration to study certain areas that are markedly hotter than their surroundings. Usually this is due to development, lack of tree cover and reflective surfaces like parking lots, county health officials said.
Data was gathered from sensors on vehicles driven by trained volunteers. They drove assigned routes at predetermined hours and the sensor recorded the temperature, humidity and location for every second driven.
The data was then analyzed by Portland, Ore.-based CAPA Strategies by combining the roadway temperatures with satellite information on land use, vegetation and development.
There was a 10-degree variation in parts of JoCo
Johnson County’s results showed some variation in where the heat was worst, depending on the time of day.
In the afternoon between 3 p.m and 4 p.m. for example, the hottest areas were over 95 degrees and the coolest around 85 degrees.
The heat index for that time period was even higher, with the hottest areas around 100.6 degrees and the coolest clocking in at 89.7 degrees.
The persistently hot areas were where researchers expected they would be — near development with vast stretches of concrete and in places where few trees are found, said county epidemiologist Jackson Ward.
“Vulnerable communities” experience more heat
Brian Alferman, the sustainability program manager for the county, said he was struck by how hot the Gardner and Edgerton area persistently was.
He and Ward said more investigation will need to be done on the data, but noted the logistics parks near the intermodal rail facility might be a factor.
The area also lacks a mature tree canopy to provide a cooling effect.
“We can expect and we know those areas are hotter. If you interviewed somebody who worked at the intermodal and took a lunch break at a table on a concrete parking lot, they could tell you it’s awfully hot out there compared to an agricultural field,” Alferman said.
He also noted that the hottest areas often coincide with disadvantaged communities.
“When you look at the heat map like this and see a red ribbon following the I-35 corridor and know where the vulnerable communities are it’s pretty striking,” he said.
What could happen next
Part of the aim of the study was to give local leaders an idea of where more attention to heat is needed.
Urban heat mapping campaigns in other cities have been used to plan tree planting programs, public transit shelters and other forms of cooling relief, according to NOAA.
County health and environment officials will continue to look at the data with closer looks at possible explanations for hot and cool spots.
Eventually, they hope to put up an interactive map with labeled streets that can be used by the public.
Go deeper: Look at the heat mapping study in more detail at the county web page.
Roxie Hammill is a freelance journalist who reports frequently for the Post and other Kansas City area publications. You can reach her at roxieham@gmail.com.
