Grim warnings are issued as oppressive heat wave in US shows no signs of slowing

At least one-third of the US population is under heat advisories and excessive heat warnings and roughly 265 million people will see temperatures above 90 degrees in the coming days — with some of the highest temperatures forecast over the southern Plains.

In Texas, some prisons are without air conditioning

Oklahoma and Texas saw some of the highest temperatures in the region Tuesday — with a record high 115 degrees recorded in Wichita Falls, Texas.

But a number of incarceration facilities across the state do not have working air conditioning, the Texas Department of Criminal Justice said.

“There are 100 (Texas Department of Criminal Justice) units, 31 have full AC, 55 have partial AC, and 14 have no AC. We take numerous precautions to lessen the effects of hot temperatures for those incarcerated within our facilities,” Amanda Hernandez, a spokesperson for the department, told CNN In an email.

“In 2022, there have been seven inmates who required medical care beyond first aid for heat related injuries, ” Hernandez said. “None were fatal.”

The Electric Reliability Council of Texas (ERCOT), the organization that operates much of the state’s electric grid, set another unofficial record for demand Tuesday, a spokesperson told CNN. Another record is expected Wednesday.

Chief heat officers helping cities cope

Jane Gilbert, chief heat officer for Miami-Dade County, told CNN’s Don Lemon Tuesday that Miami now has nearly double the days with a heat index over 90 degrees than it did in the 1970s.

“And we’re getting many, many more days with the heat index, the more extreme levels of 103, 105,” Gilbert said. “That is not only concerning to people’s health but their pocketbooks. Our outdoor workers can’t work as long, they lose work time. People can’t afford this AC, the higher electricity cost. It’s both a health and an economic crisis.”

Those without air conditioning can keep cool by leaving windows open, using fans and putting cold towels on their necks, Gilbert said. She also suggested people check on their friends, family and neighbors.

“Elderly, young children, people with certain health conditions can be more vulnerable to the heat. It’s really important to check on those people and make sure that they have the ability to take care of themselves,” Gilbert said.

David Hondula, director of the Office of Heat Response and Mitigation for Phoenix, echoed that sentiment, saying, “The heat can affect everyone, we’re all at risk.”

Hondula suggested particularly keeping an eye on community members who may not have access to regular shelter.

“If we see somebody sleeping, for example, out in the sun on a hot surface, don’t assume they’re just taking a nap. There could be a real medical emergency there and a call to 911 might be necessary,” he said.

Why heat and humidity are especially dangerous

Heat is one of the top weather-related causes of death in the US, according to Kimberly McMahon, public weather services program manager with the National Weather Service.

“Heat affects everyone by limiting the body’s ability to cool down,” McMahon said.

High humidity levels only further limit that ability.

“Sweating removes 22% of excess body heat by redirecting heat towards the evaporation of the sweat,” CNN meteorologist Robert Shackelford said. “High humidity means that there is more moisture in the air. Since there is significantly more moisture in the air, it causes sweat to evaporate slower, which leads to a slowing down of your body’s natural ability to cool. That is why heat indices on a day with high humidity can feel significantly hotter than the actual temperature of the air.”

Too much heat and humidity can lead to heat-related illnesses including heat cramps, a heat rash, heat exhaustion “and — the worst of all — heat stroke which can result in death,” McMahon said.

“Extreme heat is a real threat and needs to be taken seriously,” McMahon added.