PIERCE COUNTY URBAN HEAT MAPPING

In the summer of 2024, Pierce County did a community heat-mapping project where volunteers drove with heat sensors to collect data and produce heat maps. This was the result.

What is the problem with urban heat?

Concrete, streets, and buildings can trap heat during a heat wave making some neighborhoods even hotter. The difference in temperature between two neighborhoods in Pierce County with the same weather can be as much as 14 degrees.
Extreme heat is dangerous to our communities, especially those with underlying health conditions like heart disease. The public health burden of urban heat islands disproportionately affect low income households. Without intervention, urban heat island impacts will grow in a changing climate.
Urban heat impacts are not equitable. Communities already experiencing the impacts of air pollution, underinvestment, and structural racism are more likely to also live in our hottest neighborhoods.
Pierce County is getting hotter every year. The number of days above 82 degree F has increased more than 50% since 1980. Should this trend continue, our region will experience 42 days above 82F by 2050, and 59 by 2100.

The Process

Volunteers for the project were organized in teams of two: a driver and a navigator. Both were required to participate in a training to learn about the urban heat island effect and how to correctly use the temperature sensor. Certain speeds had to be maintained and each group was given a specific route in one of the suburbs of Pierce County, any deviations from said route had to be recorded. On August 4th, the day of mapping, each team drove their route for an hour in the morning, afternoon, and evening. There were substitute drivers standing by but everyone made all three of their routes. There were three central hubs that volunteers could visit in between their drives for snacks, refreshments, and community building. The data was sent to CAPA strategies to be curated into heat maps.