The 2021 heat dome event that occurred in the Northwest resulted in the loss of life for many in our region and made evident that additional steps are needed to prepare and protect our communities from rising temperatures in coming years. In the third edition of the Regional Climate Health Monitoring Report for Clackamas, Multnomah, and Washington Counties, heat-related illness visits, hospitalizations, and heat-related deaths were significantly higher than previous years.1 To support response to these changes over time, we developed a seasonal report for Washington County to evaluate the association of heat-related illness emergency department visits and all deaths with measures of extreme heat exposure. We explore heat-related illness visits by population characteristics (zip code, race, age, and sex), and characteristics related to increased vulnerability to extreme heat, such as access to air-conditioning. This report is meant to inform emergency preparedness and climate adaptation planning.
In this report we present information on high and low temperatures, heat-related illness (HRI) emergency department and urgent care visits (ED visits), and deaths in Washington County, Oregon during summer months (May-September). High temperatures are explored as categories of 80 to 89oF and 90oF and above to match thresholds at which new occupational policies are applied and when cooling centers are typically opened (90oF).2
We include a total of 791 heat-related illness ED visits from 2016 to 2023 in Washington County. We identify these visits using version 2 of the Heat-Related Illness query from the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE) in Oregon. We summarize information from death certificates from Oregon vital statistics on 13 heat-related death from 2014-2023 and analyze 27255 deaths from all causes between 2017 and 2023. It is important to note that information about deaths from 2023 are subject to change due to standard review processes.Impacts of climate change are best observed over a period of decades. Our report only includes more recent years because data collection of ED visits changed significantly from 2015 to 2016 and our jurisdictions at this time only had immediate access to death certificates starting in 2014.
The past three summers we have seen persistently high counts of heat-related illness (HRI) emergency department(ED) visits and days with high temperatures of 80oF or above compared to recent years (2016-2020).
Most HRI ED visits on average occur on days over 90oF. However, in 2023 a third of HRI ED visits were on days between 80-90oF. When exploring average number of ED visits by temperature we begin to see averages of 3 or more visits at 75oF
On days with a cooling temperature of 50oF or higher, average daily HRI ED visits begin to increase. When cooling temperatures are in the low 60’s, there are an average of 5 HRI ED visits, whereas on most summer days we would expect no more than 1 or 2 visits. Because there are only a few days where cooling temperatures are greater than 65oF, we are unable to reliably explore average number of visits on those days.
Most heat-related illness visits in Washington County are by men and people 18-64 years of age. A greater percent of visits for heat-related illness are by people age 65 years and older as compared to all ED visits.
At the end of June 2021 there was a notable spike in all cause deaths that coincides with the 2021 heat dome event.
What are you seeing?
The figure shows total number of summer days with high temperatures under 80oF, between 80oF and 90oF, and above 90oF. On average from 2021 to 2023 there have been more days over 80oF than other recent years.
What are you seeing
The annual number of HRI ED visits on summer days below 80oF, between 80oF, and 90oF, and above 90oF are presented below. All but 53 heat-related illness visits occurred during days with high temperatures of 80oF or higher since 2016.
What are you seeing?
Annual HRI ED visits are presented below with an overlaid line for annual average high temperatures. The average high temperatures from 2016-2020 are also treated as expected.Both in 2021 and 2022 the number of visits has been well above the expected values.
Hover over the charts to see more information
What are you seeing?
Average daily HRI ED visits by daily high temperatures are presented below. On average, heat-related illness visits begin to increase when high temperatures reach 89oF. The red line indicates 90oF because it is when most heat response protocols are started.
What are you seeing? Average daily HRI ED visits by daily cooling temperatures are presented below. For days with cooling temperatures over 50oF average HRI ED visits begin to increase from an average of 1 HRI ED visit per day to 2 or more per day. For cooling temperatures greater than 58oF the average increases to 3 HRI ED visits. Average ED visits are only presented up to 65oF because the small number of days with higher cooling temperatures result in less reliable averages.
Who is visiting the emergency department for heat-related illness versus who is visiting it for all other reasons?
Values to the left are proportions for HRI ED visits, while those to the right are proportions for all ED visits. We compare demographics by visit type rather than Washington county characteristics as defined by the census to explore potential inequities more directly related to heat. We recognize that the population with access to the ED is likely not representative of the general population and that number of hospitals reporting over time has shifted.Visits may also include repeat visits by the same person.
What are you seeing?
There are fewer HRI ED visits with unknown race or some other race alone identified for race when compared to all visits. A greater proportion of HRI visits are identified as white. This may represent true differences in visitor characteristics or more complete data for this visit type.
What are you seeing?
The percentage of visits by people 45 years and older is slightly greater among HRI ED visits when compared with all ED visits.
What are you seeing?
A greater percentage of HRI ED visits are by men than women. The opposite is true for all ED visits.
What’s happening?
Among heat-related visits from 2016-2022, 56 of 668 included mention of
lack of or non-functional air conditioning.
18 of 845 included the ICD-10 code Z59 which indicates a person
experiencing houselessness.What is happening?
Since 2015, 13 people have lost their lives to extreme heat in Washington County. Nearly all occurred after 2021, were over age 50 years, and were not married. Nearly half had non-office jobs and a slight majority were male. Most people were found in their residence, although a third were found outdoors in public spaces. The veteran community was disproportionately represented among these deaths as compared to the general population.
Hover over the charts to see more information
What are you seeing?
The graph presents the number of monthly deaths from 2020-2023 and average number of monthly deaths from 2017-2019. The average is typically treated as what we would expect based on recent years. Both in 2022 and 2023 the greatest number of all cause deaths appears to peak in June and decrease until the beginning of fall.It is important to note that many of the observed peaks coincide with COVID 19 but this pattern could be consistent with an acclimation period to increased heat.
What are you seeing?
The following graph presents weekly number of deaths during summers 2020-2023 and average weekly number of deaths from 2017-2019. The summer of 2021 there is also a notable peak during the Heat Dome event, which happened in the last week of June; and another two peaks in August and September.
Among 9281 deaths by any causes from 2017 to 2023,
696 deaths or 7.5% were in people with recorded
occupations that typically require them to be outdoors, including
agricultural and construction work.
Urban heat island data should be used to more specifically identify areas within the southwestern zip codes of Washington County where rates of heat-related illness were highest. Data should be used to inform climate adaptation planning.
The greater percentage of heat-related illness ED visits occurring on days under 90oF may reflect more effective response to more extreme heat in our region, but also warrants the exploration of expanding services to include high temperatures of 80 or 85oF. In addition, with a greater number of days exceeding those temperatures more sustainable efforts for climate adaptation are critical.
Standardized questions about access to air conditioning or cooling spaces should be developed and implemented in healthcare settings. Many providers provide description in triage notes but as heat waves increase, this will support improvement of heat response public health strategies and a pathway to referring patients to preventive resources for future heat events.
In national studies isolation is known to be a risk factor for heat-related illness and death. Based on what we have observed in the county, reaching out to vulnerable community members, especially our senior population and emphasizing the importance of checking on neighbors during heat events is critical.
Clackamas County, Multnomah County, and Washington County, 2023: Regional Climate and Health Monitoring Report. https://www.washingtoncountyor.gov/public-health/documents/2023-regional-climate-and-health-monitoring-report/download?inline.↩︎
Oregon OSHA Department of Consumer and Business Services. Heat and wildfire smoke rules- summary, 2022.https://osha.oregon.gov/OSHARules/adopted/2022/heat-wildfire-smoke-rule-summary-2022.pdf.↩︎
