Many Texans are familiar with the chorus of cicadas that fill the air on the hottest days of early July. But this week, the bugs seem especially raucous.
It could be, at least in part, a result of the heat wave that has baked the region and shows no signs of letting up. On Tuesday, the high temperature was expected to reach about 103 degrees in El Paso and San Antonio.
It’s not that individual cicadas are louder than before, said Allen F. Sanborn, a professor emeritus of biology at Barry University in Miami who has retired to central Texas. Instead, Dr. Sanborn noted that the insects appear to be active for more hours in the day.
“They start calling earlier because the minimum air temperature combined with solar radiation is reached earlier in the day,” he said. “They also call later in the afternoon and evening because they can maintain the elevated body temperatures for a longer time.”
While the cicadas sing, tens of thousands of people suffocate. A warm dome of high pressure that has parked over New Mexico and West Texas, and the rising temperatures across much of the South, from Florida to California, are expected to last at least two more weeks. Experts estimate that more than 50 million people across the United States live in areas that are expected to have dangerous levels of heat.
Around this time of year, residents of New Mexico and Arizona can typically expect some respite in the form of the monsoon season, which brings heavy thunderstorms that cool the air on otherwise scorching days.
But this year, those storms are chasing.
When they first arrive, the monsoons can make the heat even more dangerous — at least momentarily — by adding humidity to the equation, said Michael Crimmins, a professor of environmental science at the University of Arizona in Tucson. He said research is still being done to determine how climate change has affected the monsoon season, and he added that the lack of storm clouds over southern Arizona has “the fingerprints of El Niño,” a cyclical weather pattern.
For people without shelter, the relentless heat is especially dangerous.
Bob Feinman, the vice president of Humane Borders, a nonprofit organization in Tucson, said migrants walking through the Arizona desert from the Mexican border were in dire need of water during the heat wave. Recently, the water tanks that the organization placed in high-traffic areas had to be refilled more often.
“More water is being used, and more stations are needed in areas like Sonoita, just north of the border with Mexico,” he said.
Thunderstorms are likely to bring some rain to Sonoita on Tuesday, and possibly Tucson as well, but the sun was expected to continue to shine elsewhere.
The high temperature was expected to approach 109 degrees in Phoenix and 105 in Tucson, and similar triple-digit temperatures are likely to continue for at least a week, possibly approaching record levels by the weekend.
John Washington and Sheryl Kornman contributed reporting.