The New York Times reports:

A relentless heat wave is broiling the Southwest, with some 50 million people across the United States now facing dangerous temperatures. Forecasters say that the current streak of consecutive 110-degree days may end up being the longest Phoenix has ever seen, potentially breaking an 18-day record set in 1974.

Arizona’s woes have been amplified this summer by the delay of monsoons that sweep up from the Gulf of Mexico and help quench tinder-dry deserts and mountainsides. The “heat island” effect of Phoenix’s growing urban footprint means that nighttime also now swelters. The low temperature dipped only to 91 degrees before dawn on Tuesday.

All of this has added up to an ultramarathon of sweat — one that is testing whether Phoenix can adapt to a new reality of longer, deadlier heat waves at a time of water shortages and soaring housing costs that have pushed record numbers of people to sleep on baking streets and forced others to choose between paying rent or air-conditioning bills.

“We haven’t even gotten to the worst,” said Stacey Sosa, 19, a fashion-design student who grew up in Phoenix, adding that she was bracing for months of heat. “We’re just starting out.”

Heat is often described as an invisible disaster — one that leaves few visible scars like the floods ravaging towns in Vermont and upstate New York but that kills far more people every year than hurricanes, tornadoes or wildfires. [Continue reading…]