Two years after the 2021 heat dome, Washington's deadliest weather-related disaster, researchers are still trying to pin down its full impacts and what lessons can be learned.
Officials estimate 126 people died from the heat between June 26 and July 2, 2021, when Washington set 128 all-time high temperature records, including in Seattle where people sweltered in up to 108 degrees. But a new report from the University of Washington says the heat dome was likely far deadlier, with 441 more people dying during that week than would have been expected based on previous years, after accounting for COVID-19.
That's the highest estimate so far, said co-author and state Department of Health epidemiologist Kelly Naismith.
In addition, the report said, the Seattle and King County 911 system was inundated with more calls than it has ever seen in its 53-year history, and nearly a quarter of the summer's emergency visits for drownings happened during the heat dome. In total, the federal Centers for Disease Control and Prevention estimated a 69-fold increase in emergency visits for acute heat illness.
The report — led by the UW Climate Impacts Group with authors from the DOH, the office of the Washington state climatologist and Gonzaga University — details how heat waves will increasingly affect the region in the next few decades.
"While we are out of the frying pan of the 2021 heat dome, we are not yet out of the fire," the report states, offering short- and long-term solutions to help prevent deaths, particularly among vulnerable groups, during future extreme temperatures.
The report offers nine strategies for preventing heat deaths and emergency room visits.
Among them is outreach to vulnerable communities that may be hesitant to change their behaviors, even after seeing a heat advisory. Maine, for example, has set aside money for peer-to-peer wellness check programs during extreme temperatures.
Many people in vulnerable communities also don't seek cooling centers, the report said, suggesting cooling centers be led by community-based organizations to encourage use.
Adjusting building codes, incentivizing building features that reduce heat risk and increasing access to cooling devices for low-income people are other solutions. According to the report, only about a third of households that earn $50,000 or less in King, Pierce and Snohomish counties have air conditioning and only 30% of rented homes in these counties have it installed.
Following the 2021 heat dome, the Oregon Legislature passed a bill that prohibits landlords from restricting a tenant from installing or using a portable cooling device.
The report also suggests that the Washington State Department of Labor and Industries adopt more robust rules around work during extreme heat events, and increase enforcement and inspections.
L&I implemented emergency rules in 2021 and 2022 for outdoor workers, and now wants to make them permanent. The department is looking to extend protections to indoor workplaces, according to the report.
Other solutions include increasing tree canopy and shade, expanding assistance programs so low-income households can avoid high utility bills when using air conditioning, and ensuring more governmental coordination, like the city of Phoenix's Office of Heat Response and Mitigation, the first in the country.
According to the UW report, climate model projections forecast summer temperatures will rise by 4 to 6 degrees Fahrenheit in the 2050s, compared with the last half of the 20th century.
Between 1971 and 2021, Washington only saw an average of three extreme heat days per year. By the 2050s, forecasts estimate, Western Washington could get on average between 17 and 27 extreme heat days per year. The eastern side of the state might see up to 30.
It will only get worse from there, forecasts show.
Meanwhile, Washington state's population of those 65 and older is projected to grow from 16.7% to 21.7% by 2040, which means more than 2 million potentially vulnerable older residents.
Asthma and respiratory diseases, also risk factors during heat waves, are also becoming more common, and population growth has largely been concentrated in urban centers, where heat islands occur, according to the report.