An oppressive heat wave blamed for at least 13 deaths in Texas and another in Louisiana is blanketing the South

A deadly heat wave is blanketing the South and spreading eastBy MICHAEL GOLDBERG, ADRIAN SANZ and JIM SALTERAssociated PressThe Associated Press

An oppressive heat wave blamed for at least 13 deaths in Texas and one in Louisiana blanketed the South on Thursday, as authorities warned of dangerous, triple-digit temperatures.

Extreme heat and humidity increased the potential for heat-related illnesses, and lingering power outages exacerbated the misery in some areas. Officials urged residents to stay hydrated, shelter in air-conditioned rooms and check on friends and neighbors.

The unusually high temperatures were brought on by a heat dome that has taxed the Texas power grid and brought record highs to parts of that state, according to meteorologists. That dome is spreading eastward and is expected to be centered over the mid-South by the weekend.

The National Weather Service in Memphis issued an excessive heat warning for west Tennessee, eastern Arkansas, north Mississippi and the bootheel of Mississippi for Thursday and Friday as it forecast heat indexes to rise above 110 degrees (43 Celsius).

The heat posed a challenge for residents of Memphis and other Shelby County cities who still had no power after strong storms Sunday that produced winds of up to 90 mph and knocked down trees and power lines.

To get some relief while waiting for power to be restored, John Manger, 74, and his wife were sitting in shady spots outside their sweltering home in the Memphis suburb of Bartlett and taking cold showers.

“I just suck it up, with a washcloth, towel, whatever. I just sit in my chair by the window, and maybe get a breeze,” said Manger, who is retired.

As of Thursday morning, more than 20,000 homes and businesses remained without power in the county, according to the local utility, Memphis Light, Gas and Water. Dozens of crews were working to restore power, the utility said.

“Please, please, PLEASE make frequent checks on your family members, friends and neighbors today, especially if they are part of a vulnerable population,” the city of Memphis said in a statement.

Cooling centers opened, and those seeking relief from the heat also were advised to go to splash pads, libraries and malls.

Eleven of the Texas heat-related deaths occurred in Webb County, which includes Laredo. The dead ranged in age from 60 to 80 years old, and many had other health conditions, according to the county medical examiner, Dr. Corinne Stern. Also, two Florida residents died while hiking in extreme heat at Big Bend National Park. In Louisiana, a 49-year-old man died Sunday in Shreveport after he was found lying on a sidewalk.

In St. Louis, the forecast called for temperatures of around 100 degrees Fahrenheit (38 degrees Celsius) on Thursday and Friday, and 95 degrees Fahrenheit (35 degrees Celsius) on Saturday before a slight cool-down on Sunday. Smoke from Canadian wildfire s have combined with the heat and humidity to worsen air quality.

Gentry Trotter, who runs Cooldownstlouis.org, said volunteers were taking donated window air conditioners to the elderly and needy.

Trotter recently went into the home of an 83-year-old woman, measured the indoor temperature and found it was 105 degrees Fahrenheit (40.6 degrees Celsius). Still, she refused to accept an air conditioner.

“Somebody needs to convince her that if she doesn’t have a blasting air conditioner, she’s going to die,” Trotter said.