Where you live in Spokane can mean the difference between a warm day or an unbearably hot one, Gonzaga study confirms

On a summer day, volunteers drove throughout Spokane collecting thousands of measurements of temperature and humidity in an effort to map out “urban heat islands.”

The result was what they and residents knew for a long time but never confirmed with data – some neighborhoods are hotter than others because of what’s known as the urban heat island effect. It occurs when pavement and buildings absorb heat and create higher temperatures than in shaded neighborhoods.

“What it reveals is confirmation and more precision of what we expected to find, which is that different neighborhoods in Spokane experience different magnitudes of heat on a given day,” said Brian Henning, director of Gonzaga University’s Center for Climate, Society, and the Environment, which collected the data as part of the center’s “Spokane Beat the Heat” initiative.

The ultimate goal is to use the high-resolution heat maps and survey results from Spokane residents about their extreme heat experiences to develop a plan for future heat waves so that no one else dies.

Scorching temperatures killed 20 people in Spokane County in 2021, more than the previous eight years combined, according to the county. The Center for Climate launched Spokane Beat the Heat in response to the 2021 heat deaths.

“There’s no reason why anybody should be dying of extreme heat in Spokane,” Henning said.

For Spokane, extreme heat refers to days with high temperatures of at least 90 degrees and low temperatures of at least 68, according to Henning.

The National Oceanic and Atmospheric Administration funded the group’s urban heat island mapping campaign, which it conducted July 16, with a $10,000 grant, Henning said.

Spokane was one of 14 U.S. cities and counties the NOAA chose for the campaign, and the only one in the Northwest. The Center for Climate partnered with the Spokane City Council Sustainability Action Subcommittee, the Lands Council, 350 Spokane and KXLY-TV for the grant.

The official high temperature July 16 at the Spokane International Airport was 88 degrees, but Henning said temperatures reached as high as 94 degrees in parts of the city where tree coverage and green spaces are sparse or where pavement and buildings are plentiful.

Henning said community members might be more vulnerable than they realize. He said a 100-degree day in one neighborhood could mean 108 degrees in another, putting those residents more at risk.

For example, during that July afternoon, the temperature in the Emerson-Garfield, Riverside and East Central neighborhoods was as high as 93 degrees, while the Manito and Comstock neighborhoods were closer to 85 degrees.

The largest temperature difference July 16 was 13.9 degrees. That morning, it was 57.8 degrees near the Downriver Park Conservation area along North Pettet Drive and 71.7 degrees at East Trent Avenue and North Regal Street near the railroad lines.

“What we’re figuring out is exactly how much that difference can be,” Henning said.

The nearly 14-degree difference highlights the urban heat island effect in which the open, commercial area with few trees at Trent and Regal was hotter than Downriver Park, where dense vegetation and a nearby river provided a cooler environment.

Henning said people’s lives, especially young children and vulnerable adults like seniors, could be at risk when overnight temperatures do not cool off enough, such as the 71.7-degree morning in East Central Spokane.

Henning said the next phase of the project is gathering Spokane residents’ extreme heat experiences. Some of the survey questions ask whether residents have air conditioning and can afford to use it. The survey can be found at gonzaga.edu/HeatSurvey.

The goal is to get a large enough sample size from people of different income levels, so the Center for Climate can gain a sense of which neighborhoods are vulnerable to extreme heat, Henning said.

The final phase is working with the city and other entities to create solutions.

Henning said one example is changing building codes to incentivize using light-colored components for large commercial rooftops instead of black ones, so they do not retain as much heat. That also lowers energy bills.

The city could also adjust its codes to incentivize more green space in and around parking lots, Henning said.

Building or improving cooling centers is another option, he said.

Henning said the city did a good job this summer making its four libraries available as cooling shelters so people could escape the heat. Spokane Transit Authority gave riders traveling to cooling centers a free ride.

Henning said he hopes to implement at least some plans by next summer, but the progress depends on interest and capacity from the city and other partners.

He said he has had preliminary talks with the city that have been encouraging.

Tree plantings is one solution the city has implemented to bring shade and cooler temperatures, as well as a host of other benefits, to neighborhoods.

Katie Kosanke, urban forester at the Spokane Parks and Recreation Department, said her department conducted studies about canopy cover in the city, but the Center for Climate’s heat map will also prove useful.

“It really is helpful in kind of providing more information to support plantings in especially low-canopy neighborhoods, which is primarily the northeast,” Kosanke said.

Kara Odegard, city manager of sustainability initiatives, said the city is prioritizing planting in northeast Spokane, where pockets of some neighborhoods are as low as 8% canopy coverage. Odegard said downtown Spokane also needs more trees.

Odegard said the city is working with the Lands Council to plant the street trees as part of a program called SpoCanopy. The program’s objective is for every neighborhood to have 30% canopy coverage by 2030.

Kosanke said some neighborhoods, like Shiloh Hills, in northeast Spokane are as low as 11% canopy coverage. Hillyard is 13%, Nevada Heights is 13.6% and Logan is 13.9%.

Kosanke said the city partnered with the Lands Council and planted 100 trees in the spring. About 100 new street trees will be planted this month in the West Central and Bemiss neighborhoods as part of SpoCanopy, according to a Spokane Parks and Recreation Department news release.

Kosanke said the city and Lands Council are expected to team up to plant another 200 trees next year, doubling what the city typically planted. They plant magnolias, oaks, elms, ginkgos and lindens to name some.

“We’re trying definitely to add more trees and canopy cover so everybody can enjoy the benefits that trees provide,” Kosanke said.

The plantings do not include trees planted as part of other city projects, like engineering and park projects, or trees required to be planted as part of a development.

A Spokane 2020 urban tree analysis report concluded that while the size of the neighborhood contributed to the amount of tree canopy coverage, it also appeared the distribution of tree canopy correlated with a neighborhood’s income level. It said tree canopy coverage is high in South Hill neighborhoods, like Manito, and low in lower income areas like Logan.

The report said the highest tree canopy coverage was Manito at 38.5% and the lowest was Riverside at 7.8%.

“The benefits of tree canopy coverage in an urban area have been identified and are a priority for the city of Spokane to take action on to promote equity and justice across the city,” the report said.

Odegard echoed the idea of tree canopy coverage being an equity issue.

She said cities across the country have also implemented “blue infrastructure,” like splash pads and drinking fountains in parks, so people can cool off while hydrating.

“I do think that there’s a lot more opportunity for us going forward to continue to invest in that green and blue infrastructure across the city,” she said.

She said the city should partner with other jurisdictions, like the county, as well.

Gerry Bozarth, Spokane County disaster recovery specialist, said he and the Center for Climate intend to apply for a Federal Emergency Management Agency grant that would make air conditioning units available for those in need. Bozarth said the data the Center for Climate compiled will be some of the basis for future grant applications.

As part of the study, Henning said the center and its partners will develop an educational heat awareness campaign so that residents, especially vulnerable ones, know the risks associated with extreme heat and what to do and where to go during heat waves.