With Portland and much of the state under an “excessive heat watch” this weekend, Multnomah County unveiled a new tool to help the county, city and local organizations respond more effectively to severe heat.
The Heat Vulnerability Index, developed in response to the 2021 heat dome, explores the risk of extreme heat throughout the county by census tract or specific address.
It measures three concepts to define heat vulnerability: each tract’s sensitivity to heat and heat illness, the level of exposure to heat based on the environment (such as building density, tree canopy, amount of cement and concrete) and the population’s capacity to adapt to extreme heat.
The interactive map shows tracts east of Interstate 205 have a much higher heat vulnerability and heat sensitivity than other areas in the city. They also have a lower capacity to adapt to extreme heat.
That could be because the areas east of I-205 have a higher prevalence of adults with coronary heart disease, diabetes and poor physical health. They also have high populations of foreign-born residents, people who are not proficient in English and residents with lower educational attainment.
The map tool can zero in on specific populations in each location, such as people older than 65, or specific variables such as populations in rental housing or heat islands.
County officials said they hope the tool, which will be continually updated, can help local responders better understand the factors contributing to heat vulnerability in specific areas and to design appropriate interventions.
The tool is already being used by the state’s largest Medicaid insurer, Health Share of Oregon, which administers health care in the metro area. The insurer has set up a dashboard using the heat index to do outreach to people with specific health conditions who live in neighborhoods more vulnerable during a heat event, said Brendon Haggerty, the county’s Healthy Homes & Communities manager.
Other health care workers can do the same thing, he said.
“Hopefully they can keep those folks cool and safe and not in a doctor’s office or at the emergency department,” he said.
The heat index tool also can help smaller community organizations tailor outreach to specific neighborhoods and provide information in the communities’ home languages to help people access city services such as cooling centers, Haggerty said.
The county and city also plan to use the heat index to figure out where to open cooling centers, where to plant trees and what types of grants to pursue to help particular neighborhoods cope with extreme heat, he said.
– Gosia Wozniacka; gwozniacka@oregonian.com; @gosiawozniacka
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