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Protecting Communities When the Heat Is On

A thermometer showing a temperature of 100+ against a background of an urban street

Over the three weeks beginning June 25, 2021, communities across Washington State struggled with record-breaking high temperatures. On June 29, 2021, temperatures rose over 100° Fahrenheit (F) in Pullman (106°), Seattle (108°), Spokane and Vancouver (both 109°), Quillayute (110°), Tri-Cities (112°), Walla Walla (116°) and Omak (117°). According to the Washington State Department of Health, the heatwave resulted directly in 100 deaths, but researchers with the University of Washington attribute an additional 159 indirect deaths indirectly to the event.

While the 2021 heatwave (which affected five total states as well as Western Canada) was the result of an unusually strong high-pressure system that became trapped over the region, such extreme events may become a more common occurrence as a result of our changing climate.

Heat islands, or urbanized areas that experience higher temperatures due to a lack of vegetation and higher concentrations of infrastructure that absorbs and re-emits heat, can compound the problem. Within the heat island, temperatures can be 1–7°F higher in the daytime and 2–5°F higher in the nighttime than temperatures in outlying areas. Additionally, heat islands are unevenly distributed across the landscape, with the impacts falling more heavily on low-income communities, especially those with higher proportions of people of color (studies have found the historical practice of redlining to be a factor).

This blog will look at how local agencies have been preparing for extreme heat events.

Collecting Relevant Data

The federal government has been aware of the dangers of extreme heat for many years. It established the interagency National Integrated Heat Health Information System (NIHHIS) to develop and provide actionable, science-based information to the public and policymakers on extreme heat.

NIHHIS also offers funding and technical support so that urban areas can conduct community-based Urban Heat Island Mapping campaigns (urban areas can apply for future campaigns). These campaigns send hundreds of volunteers across a jurisdiction in a single day to take temperature measurements throughout the day and across neighborhoods. Such campaigns provide participating cities with the data needed to identify heat islands and those residents adversely impacted by them.

Spokane was one of 14 cities in the United States chosen for NIHHIS’ 2022 campaign. The city partnered with Gonzaga University to develop Spokane Beat the Heat, which combined a citywide heat-mapping effort with extensive community outreach to learn how Spokane residents understand and respond to extreme heat events. Data Walks are happening this May so researcher can present mapping results to the public and learn more about the barriers residents experience when trying to access resources during extreme heat events.

King County and Seattle were part of NIHHIS’ 2020 heat mapping campaign. Since then, King County has committed to creating an extreme heat mitigation strategy and pursued the following steps to mitigate rising temperatures:

Some cities have independently conducted campaigns, including Shoreline and Tacoma. Tacoma created a heat map in 2020, in part to determine which areas of city to target for increasing the city's tree canopy cover from 20% to 30% by 2030, per the 2015 One Tacoma Comprehensive Plan. The city then developed a tree equity map to understand where increasing the canopy could have the greatest impact.

Practical Approaches to Countering Heat Islands

To help with heat islands communities can adopt any number of approaches, including: 

  • Planting trees (for shade) and other vegetation (to reduce runoff),
  • Maintaining/protecting the urban canopy,
  • Encouraging the development of shade structures,
  • Replacing normal pavement with cool pavement,
  • Painting roofs white, or
  • Adding water features to neighborhoods.

Snoqualmie offers an example of how a smaller city can work to protect the existing tree canopy. It steadily built its urban forestry program from the ground up over a 12-year period. Using state funding, the city conducted a tree canopy assessment in 2012 and completed an Urban Forest Strategic Plan in 2014, which, among other things, called for the city to create an urban forestry program. The city conducted another tree canopy survey in 2015 to document any changes in coverage since 2011, and in 2016, the King Conservation District’s Urban Forest Health Management Program helped Snoqualmie develop a community stewardship and forest management plan (2017) for the city’s forestland. Additionally, the city passed Ordinance 1198 (see Exhibit A, pages 45-51) amending Chapter 13.10 of its municipal code, designating urban forestry as an appropriate use of stormwater utility funds. The city now has a stable funding source from which to further develop the urban forestry program.

Several local governments work with partners to protect the local tree canopy, including:

  • King County: 3 Million Trees — which is targeting to plant and protect three million trees throughout the region by the end of 2025.
  • Seattle: Trees for Neighborhoods — which offers vetted free trees to resident. The program helps residents obtain permits, site and plant trees, and it monitors the health of planted trees for the first few years.
  • SpoCanopy — which plants free street trees in low-income neighborhoods with low canopy coverage and disproportionate environmental disparities.
  • Whatcom County: Million Trees Project — which plants trees in parks and public/semi-public spaces and protects mature trees in the Lake Whatcom watershed and county urban forests.

Operating Cooling Centers

When the heat is on and residents need a place to seek relief, local governments can offer cooling centers.

Common cooling center sites include community centers, library branches, senior centers, and locations in a government building (such as city hall chambers). Less common sites include colleges (e.g., Renton Technical College) area malls, or churches/nonprofit partners.

When identifying a site, it’s important to consider the barriers that may preclude a person from using the site — Will it serve families? Will it allow pets? Will free transportation be available to/from the location? It’s also important to consider equity-related questions, such as which neighborhoods are most at risk? Tacoma’s Climate Change Resilience Study Summary identifies cooling center sites as “public libraries and the Tacoma Mall” but notes that “South Tacoma, New Tacoma (near downtown), the southwest area of West End, and Eastside” are particularly in need of assistance for extreme heat preparedness.

Spokane Municipal Code Ch. 18.05 covers the conditions under which the city will open a cooling center and advises the city to develop “a network of…locations…at schools, libraries, churches and community centers and encourage other municipal governments to join in providing a regional cooling center network.”

For more information on operating a shelter for severe weather emergencies, see MRSC’s blog, Severe Weather Shelters for Winter and Beyond.


Heat-related deaths and illnesses are preventable, and local governments can take steps to help residents, infrastructure, and systems reduce their vulnerability to heat, both in response to extreme heat events and as part of long-term planning to lessen future risks.

MRSC is a private nonprofit organization serving local governments in Washington State. Eligible government agencies in Washington State may use our free, one-on-one Ask MRSC service to get answers to legal, policy, or financial questions.

Photo of Leah LaCivita

About Leah LaCivita

Leah joined MRSC as a Communications Coordinator in the fall of 2016 and manages MRSC’s blog and webinar training program, in addition to developing website content.