What can be learned from the Pacific Northwest’s 2021 heat wave

Heat waves in 2021 also increased illness or injuries, leading to higher use of healthcare services. Nearly a quarter of emergency visits for drowning or submersion in the summer of 2021 occurred during the heat dome, and overall visits were double the weekly average.

The report notes economic losses that are likely attributable to the heat’s impact on health. While there wasn’t a specific economic assessment for the 2021 heat dome, researchers said the unprecedented and widespread extreme heat likely contributed to higher financial losses that year because of heat-related illnesses, traumas, loss of life and reduced productivity. The state Department of Labor & Industries reported that Washington could lose between $111 million and $153 million annually from extreme heat.

Extreme heat will continue

The report notes that between 1971 and 2021, the state experienced just three extreme heat days per year, defined as days when temperatures are above the 99th percentile of historical temperatures for that day. Those numbers are expected to increase with continued warming: Climate models project that by the 2050s, Pacific Northwest summer temperatures will increase 4 to 6 degrees Fahrenheit by the 2050s compared to the last half of the 20th century.

As a result, the number of extreme heat days will increase, which means that by the 2050s, Western Washington could see 17 to 27 heat days and Eastern Washington 20 to 30. By the 2080s, research indicates, extreme heat days in Eastern and Western Washington could number in the low 20s at the minimum, possibly up to nearly 50.

While an increase in heat days could negatively affect the general population, specific populations will bear the brunt of the impacts: those with chronic medical conditions, unsheltered residents outside or in marginal housing and those working outdoors.

Taking action

The report emphasizes the importance of individuals, community groups and governments adopting strategies to protect residents from extreme heat and prevent illness and deaths.

Groups that could have resources to take action include municipal planning agencies, local parks departments, local health jurisdictions, churches, state agencies and individuals and families.

Researchers also made recommendations for individuals, such as taking the initiative to prevent heat-related illness and responding to signs of heat exhaustion, heat stroke and other illnesses caused by extreme high temperatures.

The report also recommends emergency responses such as door-to-door and telephone checks of vulnerable and hard-to-reach people and creating air-conditioned cooling centers and residency hubs where people can either escape the heat or get supplies and other services to get through the emergency.

The report said governments and lawmakers must consider extreme heat as a factor in future policies, such as creating building codes and urban development plans that can help buildings and public spaces maintain tolerable temperatures, increasing tree canopy and shade structures to minimize heat exposure, and protecting workers with laws such as Washington’s newly proposed heat protection rules.

The report also recommends that each community determine how and when to implement different strategies. For example in Spokane, Gonzaga University researchers collected data to determine which areas of the city reported the hottest temperatures in 2021. The researchers also collected surveys to assess individuals’ experiences with extreme heat, which revealed, among other things, that a quarter of respondents didn’t have air conditioning and an additional portion had air conditioning but found it too expensive to use. The report said the research led to the development of the city of Spokane’s extreme-heat response plans and a public awareness campaign in the works.

The full report, with resources on preparing for and mitigating extreme heat conditions, can be found on the University of Washington’s Climate Impacts Group’s website.