2021 heat wave contributed to over 150 deaths across Washington state, study finds

SEATTLE — A recent study from the University of Washington is renewing warnings that heat may be a silent killer.

The study led by Joan Casey, a professor in the school’s Department of Environmental and Occupational Health Sciences, shows that the heat wave that hit Washington in 2021 contributed to 159 deaths over three weeks.

Official estimates from the Washington State Department of Health only included people killed directly by heat exposure.

But the UW’s study includes deaths that the heat wave contributed to indirectly, including drownings, transportation accidents, violence and self-harm.

Researchers say that this expanded measure captures the true toll of the heat waves, noting correlations between temperature spikes and deaths from injuries.

“Official death tolls may miss deaths not immediately and obviously tied to high temperatures, but those previously counted may represent just the tip of the iceberg, to use a poor analogy for a heat wave,” said Casey.

Researchers are now calling on public health officials to plan for the potential widespread impacts of future heat waves.

“Public health officials should allocate a portion of their budget to these extreme but increasingly common events,” Casey said. “Communities require additional support for things like cooling centers — especially in places like the Pacific Northwest, where air conditioning is not common.”

Specific actions researchers recommended include promoting safe swimming to prevent drownings and offering increased mental health services.