About this report
Health Effects of Summer Hazards
Experiencing high summer temperatures without relief from the heat and knowledge of protective health measures can lead to illness, hospitalization and death in severe cases.[1][2]. The heat can stop a person’s body from regulating internal temperature, increasing their risk of experiencing heat-related illness such as heat cramps, heat exhaustion, heat stress and heat strokes[3]. Extended periods of extreme heat may also create conditions for other summer hazards. These may include poor air quality from wildfire smoke and extended allergy seasons, as well as injuries or drowning from recreational water-based activities as people try escaping the heat[4].
Historically, Washington County’s communities had milder summer temperatures with few days over 90°F, and periods of low temperatures that gave enough relief without air conditioning. In recent years however, the average annual temperatures and number of days with temperatures over 90° F in the Pacific Northwest have increased. This summer hazards report presents Washington County resident’s data on emergency department and urgent care visits for heat-related illness, asthma-like illness, fire and smoke inhalation, seasonal allergies, recreational water exposure, non-infectious respiratory illnesses, submersion and non-fatal drowning. The goal of this report is to help communities better understand health effects of summer hazards, so we can better prepare, respond and adapt.
Key Takeaways
The number of heat-related illness emergency department and urgent care (ED/UC) visits during summer months since 2021 has been greater than previous years.
Although Oregon has historically had mild weather, recent years show that communities faced at least 12 days annually of moderate heat exposure during summer months.
When compared with all-cause ED/UC visits, a larger percent of heat-related illness visits had three common factors: They were by males, people 65 years and over and people identifying as white alone.
In each of the past four summer seasons, we have lost at least one Washington County resident to drowning, and have had at least 12 ED/UC visits due to drowning . Most of these visits have been by children.
Methods
Quantitative
Summer ExposureWe report number of days based on categories of heat risk in Washington County, from 2018 to 2025, during the summer months of May 1 to September 31.
We report the number of summer season days with different levels of the National Weather Service heat risk. This is a color-numeric-based index that provides a forecast for risk of heat-related impacts to occur over a 24-hour period. It considers:
How usual the heat is for the time of the year
The duration of the heat including both daytime and nighttime temperatures
If those temperatures pose a higher risk of heat-related impacts based on data from the CDC
More information can be found on NOAA’s “Understanding Heat Risk” document
We report on the Air Quality Index (AQI). The U.S. Air Quality Index (AQI) is Environmental Protection Agency’s (EPA) tool for communicating about outdoor air quality and health. The AQI includes six color-coded categories, each corresponding to a range of index values. The higher the AQI value, the greater the level of air pollution and the greater the health concern.
- Good: AQI between 0 and 50
- Moderate: Between 51 and 100
- Unhealthy for Sensitive Groups: Between 101 and 150
- Very Unhealthy: Between 201 and 300
- Hazardous: Between 301 and 500
More information can be found on the Air Now’s Air Quality Index (AQI) Basics page
Health OutcomesWe explain how summer hazard weather conditions are related to health emergencies like heat-related illness, asthma, smoke inhalation, non-infectious respiratory illness, seasonal allergies, recreational water exposure injury, and drowning and submersion in each tab.
We describe and analyze emergency department and urgent care (ED/UC) visits from the Oregon Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE) ) from 2018-2025 summer seasons (May 1- Sept. 31) by Washington County residents. For each of the queries, we present:
Annual counts that include average count for the entire period as a reference
Rates of ED/UC query-specific visits among all-cause visits that are ranked by zip code during all 2019-2025 seasons
Comparison of demographic distributions (i.e., age, sex, and race/ethnicity) for ED/UC query-specific visits and all-cause visits during 2021-2025 summer seasons that include note of statistically significant differences (p < 0.05) based on chi-square and Fischer tests with a *, and sizeable differences with ^ (absolute difference of 5 percentage points).
This data was updated on July 10, 2025.
We analyzed mortality data from Oregon Vital Statistics for deaths that happened in Washington County from 2018-2025. We used that to identify andreport the number of heat-related deaths, respiratory deaths, deaths from drowning, and all-cause deaths by summer season (May 1 to Sept.31).
Qualitative
From 2023-2024, Washington County partnered with Rede Group to conduct phases one and two of a community engagement process to inform public health modernization plans[5]. These plans include the Climate Action Plan and All Hazards Preparedness Plan.
We conducted a third phase – funded by the Department of Energy through the Energy Efficiency and Conservation Block Grant – to further inform the Climate Action Plan. In the context of climate change and health, we asked participants about climate preparedness, needs, and sources of resilience during all phases of engagement.
All phases include a total of 759 participants who took part in surveys, tabling events, knowledge exchanges, interviews and focus groups. This report shares quotes from the people participating in engagements focused on climate change and emergency preparedness. Participants included people identifying as Latino/a/x/e, Chinese American, Vietnamese, African American, Native Hawaiian, Pacific Islander, American Indian and Alaska Native, Russian, Ukrainian, Arabic-speaking, Somali-speaking, Pashto-speaking, and other immigrant and refugee communities. People and organizations also represented youth, students, older adults, individuals who identify as Lesbian, Gay, Bisexual, Transgender, Queer/Questioning and other gender identities and sexual orientations, people with disabilities, unhoused individuals, and individuals experiencing food insecurity.
Community Engagements by Phase are summarized below:
| Phase 1 and 2 | Phase 3 |
|---|---|
| Phase 1 (Aug-Oct 2023)|Phase 2 (Apr-Aug 2024) | Apr-May 2025 |
| Five individual interviews with community partners and organizations Three knowledge exchanges with community members in partnership with Bienestar, African Youth and Community Organization, and home visitors from Washington County Public Health’s Maternal, Child, and Family program One focus group with Pacific University students Five tabling events including Juneteenth Celebration, Tauraro Fest, Tigard Pride Festival, Beaverton Pride Festival, and the Adelante Mujeres Forest Grove Farmers Market Two survey efforts at Cedar Halal Market and Islamic Social Services of Oregon State food pantry **Emergency Preparedness (180 participants)** Eight individual interviews with community partners Six knowledge exchanges with CHWs, partners who belong to Washington County’s Community Participation Organizations, and community members who identify as disabled, are BIPOC and speak Russian One tabling event with Adelante Mujeres at the Forest Grove Farmers Market Three focus groups with community members from Washington County and Pacific University students |
**Climate Change (176 participants)** One Community Survey Four focus groups including: • Members of a senior community center • • Washington County’s Community Participation Organizations • Advisory council on racial equity • Native Hawaiian and Pacific Islander (NHPI) community members |
Two people reviewed triage notes, chief complaints, discharge diagnosis and ICD codes sections of heat-related illness visits during 2025’s warm season (May-Sept.) to identify common exposure circumstances (i.e., outdoor exposure, ambulance use, occupational, recent trauma history before injury, exposure in a vehicle, houselessness, pregnancy, intoxication, and special event participation) and existing conditions and disability (i.e., chronic condition, disability, mental health, diabetes, and cardiovascular disease). Categories mentioned in 10 or fewer visits were consolidated into broader groups to lower their risk of being identified.
Data details
Daily data on heat risk for Washington County comes from National Weather Services. The data on Air Quality Index (AQI) comes from the EPA. Measures of AQI 24-hour averages were taken from all air monitor stations in Washington County, and results from the air monitor with the highest daily index were included in this report.
The number of emergency department and urgent care (ED/UC) visits for heat-related illness, seasonal allergies, asthma-like illness, fire and smoke inhalation, non-infectious respiratory illness, recreational water exposure, and submersion and non-fatal drowning, and all-cause visits came from Oregon’s ESSENCE database. All visits were by Washington County residents.
Data on deaths came from death certificates from Oregon Vital Statistics from 2018-2025 summer seasons. Deaths described in this report occurred in Washington County and may include non-Washington County residents.
Data in this report are for the months of May-Sept.from 2018-2025, referred to as summer months or seasons. Queries used to define health outcomes in this report are detailed in the table below.
| Health Outcome | Data Source | Query Text |
|---|---|---|
| Heat-related illness (ED/UC Visits) among county residents | Oregon ESSENCE | Keywords in patient records that suggest heat illness, such as: 'heat stroke', 'heat exhaustion', 'too hot', 'hyperthermia', 'sunstroke', 'heat cramps' and other variations like 'hot' with 'fatigue,' 'exposure,' or 'cramps.' ICD 9 and 10 Codes: T67, 992 |
| Seasonal Allergies (ED/UC visit) among county residents | Oregon ESSENCE | Keywords in patient records that suggest seasonal illness, such as any mention of 'allergy' or 'allergies'. This identifies patients who might be reacting to pollen, dust, or seasonal environmental allergens (e.g., grasses, trees, weeds). |
| Asthma-like illness (ED/UC visit) among county residents | Oregon ESSENCE | Keywords in patient records include: 'asthma' (including misspellings like 'asma,' 'asthmae,' 'asthmia'), 'bronchospasm' (tightening of the muscles around the airways), 'reactive airway disease,' 'airway disease'. |
| Fire and Smoke Inhalation (ED/UC visit) among county residents | Oregon ESSENCE | Keywords in patient records include: wild fire or wildfire, the word 'smoke,' but not when it's part of common phrases that don't indicate environmental exposure. |
| Non-Infectious Respiratory Illness (ED/UC visit) among county residents | Oregon ESSENCE | Keywords in patient records indicating chronic or acute lung conditions like: Asthma, COPD, Chronic bronchitis, Emphysema, Acute bronchitis (without infection), Bronchial asthma |
| Recreational Water Exposure (ED/UC visits) among county residents | Oregon ESSENCE | Keywords in patient records: Lake, river, boat, swim |
| Submersion and non-fatal drowning (ED/UC visits) among county residents | Oregon ESSENCE | Keywords in patient records includes mentions of drowning, but not feelings of drowning. This includes the word 'DROWN', but excludes phrases like: 'FEEL DROWN,' 'FELT DROWN'. |
| Heat-Related Deaths that occurred in the County | Oregon Vital Records | ICD 10 Codes: X30, T67, and P810 |
| Respiratory Deaths that occurred in the County | Oregon Vital Records | ICD 10 Codes: J20, J43, J44, J45, J80, R060, R0602, R0609, J96 |
Acknowledgments
Land Acknowledgement (as prepared by representatives of Confederate Tribes of Grand Ronde, Nez Perce, Siletz, and Yavapai)We want to acknowledge the people on whose land we live — the Atfalati-Kalapuyans, also known as the Tualatin Band of Kalapuyans — the first inhabitants of Washington County. We are grateful for the land we are on, Kalapuyan land.
Signers of the Willamette Valley Treaty of 1855 were removed from their homelands to the Grand Ronde Indian Reservation. Today, their descendants are tribal members of Grand Ronde and Siletz tribes, carrying on the traditions and cultures of their ancestors.
We acknowledge and express gratitude for the ancestors of this place and recognize that we are here because of the sacrifices forced upon them. In remembering these communities, we honor their legacy, their lives and their continuation in our community. Please reflect on the role government has played in the painful, colonial history and reflect as well on the resilience and healing of the Indigenous land and communities.
We would like to invite everyone to collaborate and work together with the tribes to take care of the land and water and the people who inhabit these spaces.
Community partners AcknowledgementWe would also like to acknowledge community members and partnering organizations interviewed for their dedication to communities and willingness to share experiences and stories that give critical context to how we track and respond to impacts of summer hazards on the community.
Resources
For more information on how to stay cool, go to the County’s Hot Weather page
Thank you again to our community who supported collection of information to identify heat islands in our community! This work continues to inform our County climate and health planning and is another reminder of the strength of working together as a community. View results from the heat mapping campaign
Notes
Common terms and abbreviations:
ED/UC: Emergency Department and Urgent Care Visits
ESSENCE: Electronic Surveillance System for the Early Notification of Community-Based Epidemics
Summer Seasons: In this report we refer to the months from May to September because these often are the months with the warmest weather.
AQI: Air Quailty Index
EPA: Environmental Protection Agencies
CDC: Center for Disease Control and Prevention
References[1] Voelkel J, Hellman D, Sakuma R, Shandas V. Assessing Vulnerability to Urban Heat: A Study of Disproportionate Heat Exposure and Access to Refuge by Socio-Demographic Status in Portland, Oregon. Int J Environ Res Public Health. 2018;15(4). ↩︎
[2] Mahsin MD, Cabaj J, Saini V. Respiratory and cardiovascular condition-related physician visits associated with wildfire smoke exposure in Calgary, Canada, in 2015: a population-based study. Int J Epidemiol. 2022; 51(2): 166-178. ↩︎
[3] CDC. National Institute For Occupational Safety and Health(NIOSH): Heat Stress Heat-related Illness. 2025; https://www.cdc.gov/niosh/heat-stress/about/illnesses.html. Accessed April 2025. ↩︎
[4] Sindall R, Mecrow T, Queiroga AC, Boyer C, Koon W, Peden AE. Drowning risk and climate change: a state-of-the-art review. Inj Prev. 2022; 28(2): 185-191. ↩︎
[5] Rede Group, on behalf of Washington County Public Health Division. Community Engagement Findings to Support Public Health Modernization. Washington County, OR; October 2024. https://www.washingtoncountyor.gov/public-health/documents/community-engagement-findings-support-public-health-modernization/download. Accessed June 12, 2026 ↩︎