As record highs are being broken throughout the Pacific Northwest, the lack of air conditioning in many homes in such cities as Portland and Seattle could make an already brutal heat wave even more dangerous.

The temperature in Portland spiked on Sunday to 112 degrees Fahrenheit, easily smashing the previous record of 108 from just the day before. The high in the city this time of year averages in the 70s.

In Seattle, it was so hot that the city closed a community pool due to "unsafe, dangerous pool deck temperatures," The Associated Press reports.

A forecast discussion posted by the National Weather Service in Seattle/Tacoma on Sunday gave this sobering assessment: "As there is no previous occurrence of the event we're experiencing in the local climatological record, it's somewhat disconcerting to have no analogy to work with. Temperature records will fall in impressive fashion. Stay cool, stay hydrated."

But staying cool could prove especially difficult in Seattle, which ranks as the least air-conditioned city in a comparison of the top 15 metro areas contained in the U.S. Census Bureau's most recent American Housing Survey from 2019. Nationwide, about 91% of U.S. homes have primary air conditioning installed, according to data from the American Housing Survey. By comparison, that figure is 78% for Portland and just 44% for Seattle.

"The Pacific Northwest, west of the Cascade mountains, has a history of very mild summers, so the need for cooling has not been a strong driving force," Wes Davis, the director of technical services for the Air Conditioning Contractors of America, wrote in an email to NPR.

Meanwhile, for the service technicians who are being called on to repair existing air conditioning units during the current heatwave, "everyone is just swamped," says Dan Pfau, executive director of the Oregon Air Conditioning Contractors Association.

"Every contractor in town is just deluged," he says of the OACCA's headquarters in Vancouver, Wash.

Pfau tells NPR that the COVID-19 pandemic has made matters worse due to disruptions in supply chains for HVAC parts coming from Asia.

According to the Mayo Clinic, a "lack of air conditioning" is one of several contributing factors in heat stroke — a condition that causes the body to overheat and can lead to death.

"Fans may make you feel better, but during sustained hot weather, air conditioning is the most effective way to cool down and lower humidity," according to the Mayo Clinic's website.

Seattle has opened cooling centers in libraries, senior centers and other community facilities to offer residents a respite from the heat.

Copyright 2021 NPR. To see more, visit https://www.npr.org.