Nearly one-third of the US faces excessive heat

Ice and water is distributed to the homeless in Oklahoma City on July 19 as temperatures reach 110 degrees (43.3 deg C). PHOTO: NYTIMES

NEW YORK (NYTIMES) - About 100 million Americans from California to New England had sweated through heat advisories and warnings from the National Weather Service on Wednesday (July 20), as a brutal heatwave across the central part of the country showed no signs of letting up.

Heat warnings and advisories were put in place for parts or all of 28 states. People in the Southeast and the Southern Plains faced the most oppressive temperatures, with triple digits expected on Thursday and beyond across parts of Oklahoma, Texas, Arkansas and Louisiana, said Andrew Orrison, a weather service meteorologist.

Oklahoma City broke a daily heat record on Tuesday dating back to the Dust Bowl era with a temperature of 110 Fahrenheit (43.3 deg C)- tied for the state's highest-ever July temperature, the weather service said - and Austin, Texas, on Wednesday saw its 40th straight day of highs over 100 degrees Fahrenheit (37.8 deg C).

"These are definitely dangerous heat conditions," Orrison said.

The Dallas area has had more than two dozen days of triple-digit heat this year, including 16 in July, and highs there were expected to top 100 degrees Fahrenheit every day for the next week. The average number of 100-plus-degree Fahrenheit days in Dallas for an entire year is 20, said Madison Gordon, a weather service meteorologist.

The extended heat and lack of rain has caused the ground to shift in Fort Worth, Texas, causing nearly 200 water main breaks over the past month. And Oklahoma's largest ambulance service said earlier this week that it had seen a surge in heat-related health emergencies in Oklahoma City and Tulsa.

On the East Coast, heat advisories were in place along much of the Interstate 95 corridor from Philadelphia to Boston, as well as across parts of upstate New York and southern New England. Actual highs will be in the mid-to-upper 90s, while heat indexes will reach 105 degrees. With the heat expected to intensify through the weekend, several cities opened cooling centres for residents.

The Boston area was expected to see five or six consecutive days hotter than 90 degrees this week and through the weekend, said Kyle Pederson, a weather service meteorologist in New England. The last time the city saw six consecutive 90-plus-degree days was in July 2016. The average temperature in Boston for this time of year is 83 degrees.

New York City was also forecast to see above-normal heat through to Tuesday, said James Tomasini, a weather service meteorologist in the city. Temperatures will be in the high 90s; the average for July is 84 degrees.

California's Central Valley also had excessive heat warnings in place on Wednesday, although that is not unusual for this time of year.

It's difficult to blame any particular heat snap on climate change without extensive scientific analysis, but heatwaves like the ones in Europe, Asia and North America this summer are typical of what scientists expect as the Earth warms - more frequent, longer lasting and more dangerous.

Heatwaves in the United States jumped from an average of two per year in the 1960s to six per year by the 2010s. And it's all part of an overall warming trend: The past seven years have been the warmest in the history of accurate worldwide records.

The relentless heat afflicting the middle of the country showed no signs of ending through at least the rest of July - and could extend to places that have been largely spared so far this summer, as the Northeast had been until this week.

A high-pressure heat dome was forecast to expand to more parts of the West and East Coasts by the weekend and into early next week. The weather service is already anticipating heat warnings for the Pacific Northwest this weekend, Orrison said.

Several of the records being broken across the Southern Plains this week were set during the heatwaves of the 1930s, when the Dust Bowl decimated agriculture and the economy.

"The fact that we're seeing these temperatures kind of get close to what happened back then, just kind of shows the impressiveness or the magnitude of the heatwave we're currently seeing," Orrison said.

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