Two days after Hurricane Beryl struck Texas, Janet and Pamela Jarrett’s Houston home was still without power and a heat watch was in effect.

They spent the evening playing Pamela’s favorite game, Connect 4. All seemed well.

But early the next morning, Janet found Pamela, 64, who is disabled and in a wheelchair, struggling to breathe.

“I could hear her gasping for air and breathing heavily,” Janet said. “It’s something you never forget. It never goes away. I can hear it even when I’m lying down to sleep. It feels like I’m going through it all over again.”

Pamela died on the way to the hospital on July 11. The official cause of death was: Environmental Heat Exposure.

Of the 21 confirmed deaths in Texas from Hurricane Beryl, one-third died the same way: not from typical storm threats like flooding or downed trees, but as a result of extreme heat caused by widespread power outages during and after the storm. Heat indexes, or “feels like” temperatures, rose into triple digits in the days following the storm.

These tragedies highlight how ill-prepared Texas (and much of the rest of the country) is for the increased frequency and intensity of extreme weather events caused by climate change, especially when multiple hazards overlap. The death toll also shows how easily the line can become blurred between one type of deadly environmental hazard and another.

The death toll from Beryl in Texas is expected to continue to rise, and the increase in deaths from heatstroke has led to increased scrutiny of local power company CenterPoint Energy and the state government.

“She didn’t have to die like that,” Janet said of her sister. “I’m angry that I didn’t get a response. I couldn’t call anyone. I’m angry that CenterPoint didn’t do a better job. I’m just angry about the whole thing.”

More than 2 million homes and businesses were affected by power outages caused by Category 1 Hurricane Beryl. CenterPoint said in a statement to NBC News that it would be conducting a “thorough review” of its response to the storm.

“Our condolences go out to the families and friends of those who lost their lives as a result of Hurricane Beryl,” the power company said.

CenterPoint officials insist the company mobilized crews as quickly as possible and did everything in its power to resolve the outage.

Janet Jarrett was forced to go without electricity for a total of nine days, during which indoor temperatures soared to nearly 100 degrees Fahrenheit at night. She spent a week in that heat after her sister died.

Janet said she did her best to keep Pamela cool, using cold rags and taking her outside in her wheelchair when it was windy, but as with most patients with heatstroke, by the time the symptoms became apparent it was too late.

“I didn’t know there was anything really wrong with her,” Jarrett said. “She was talking, she was reacting to everything, she was just normal, so I didn’t realize anything was wrong.”

Jesus Rodriguez, 52, of Houston, also had no idea that anything was wrong with his 78-year-old father, Oscar. On July 10, the third day of the blackout, Jesus went to check on Oscar in the morning, grabbing some water and a cold diet coke from the cooler.

When Jess got home that afternoon, her dad “was lying on his back, almost like he was asleep, but he was breathing heavily,” Jess said. “I didn’t think anything of it, but I tried to wake him up, but he wouldn’t wake up. That’s when I called 911.”

Oscar died that day at Memorial Hermann Greater Heights Hospital in Houston. Jess described her father as a healthy man for his age and a devoted family man.

There have been power outages during previous storms, but never for more than two days.

“This was definitely the worst,” Jesus said. “It took almost a week and a half to get the electricity restored.”

He blamed CentrePoint for being slow to respond and for not communicating well enough.

“If they had said, ‘We can’t get to your house in a week and a half,’ I might have been able to send my father somewhere else,” Jesus said.

Three Houston-area hospitals reported a significant increase in emergency room visits due to the post-storm heat.

Dr. Ben Saldana, associate medical director at Houston Methodist Hospital, said the hospital has seen its highest number of emergency room visits since the 2021 Texas cold snap.

“On the day of the storm, our emergency department saw almost double the normal volume of patients,” Saldana said, adding, “We’re not back to normal yet.”

Doctors at the hospital said they have linked health issues in 525 patients to the effects of heat since the Fourth of July.

Even those whose lives were not in danger from the heat described the harsh conditions caused by the power outages.

Deja McClendon of Humble, Texas, was without power for six days and had been shuttling between her apartment, her boyfriend’s mother’s apartment, and a hotel to escape the heat. She said the chaos had forced her to take time off work.

“Texas is something else when it comes to the heat,” McClendon said, adding, “It was very stressful having to move around so much.”

Talulah Christie, who is five months pregnant, was without power for five days in Conroe, Texas, which is served by Entergy Texas. She said the outages after Beryl were the worst she could remember.

“I tried to endure [the heat] “After the first two days, and then the second night, I knew this was becoming a medical issue. I couldn’t stay here,” she said. But she and her husband couldn’t find an affordable hotel room nearby, so they stayed.

Texas Governor Greg Abbott has called for an investigation into CenterPoint’s response after the hurricane, but he has himself faced criticism for being on an economic development trip to Asia when the storm made landfall.

The utility has also been blamed by Democratic Rep. Sylvia Garcia of Texas, whose district saw several heatstroke deaths after Hurricane Beryl.

“The extreme heat exacerbated the public health crisis because CenterPoint failed to quickly restore power,” she said in a statement to NBC News.

Janet Jarrett said she hopes preventative measures are taken to prevent others from suffering preventable losses.

“This should never have happened. We had so many plans and they took it all away from her,” Jarrett said. “And now I’m burying her.”