“We don’t have anything to eat,” said Nelsey Alvarez, 34, a single mother from Honduras who said she had never faced such a power crisis in her native country, where hurricanes are common. “When they lose power, they restore it the same day.”

But the Houston-area utility, CenterPoint Energy, was particularly vulnerable. Its grid, according to data collected by the firm Whisker Labs, which tracks power outages through devices in ratepayer homes, is one of the most unstable in the United States despite Houston’s hurricane-prone Gulf Coast location. Whisker found that even before the storm hit Monday, outages in CenterPoint’s service territory were happening at more than twice the national average.

“This was one of the most challenged grids in the country,” Whisker chief executive Bob Marshall said. “This needs to be a shocking wake-up call. It was just a Category 1 hurricane, something Houston should be able to deal with. It could have been much worse. Yet 40 percent of the utility’s customers are without power in 100-degree heat and high humidity. It is a horrendous situation.”

CenterPoint officials said they had not reviewed the Whisker data but pushed back on the finding that their system is one of the country’s most unreliable.

“Our system is in great shape,” said Darin Carroll, the company’s senior vice president for operations. “As it relates to this storm it actually operated as designed.” He pointed to the speed with which CenterPoint was able to restore power to 1.1 million customers by Thursday and noted hundreds of thousands more will come online Friday and over the weekend.

But 500,000 ratepayers are still likely to be without power by early next week, according to Carroll, a full week after the storm blew through. Health and safety risks from power outages quickly supplanted the immediate storm toll.

At least nine people have died in Texas and Louisiana after the storms — people who were killed by falling trees, who drowned after being trapped in vehicles in rising floodwaters, or who were left vulnerable during power outages. Now, there are concerns the outages could cause more casualties as heat indexes surge into the triple digits.

Gov. Greg Abbott (R), who is traveling in Asia on an economic development trip, on Wednesday called for an investigation into why the Houston region has repeatedly endured long-term, widespread power outages. Other elected officials also demanded accountability.

“People are angry,” Houston Mayor John Whitmire said. “I share their anger and frustration.”

It is becoming a familiar story in the United States.

One power company after another finds itself facing irate customers — and mounting litigation — amid failures to prepare for extreme weather events that are increasingly common in the age of climate change. The slow pace with which utilities are upgrading their infrastructure is not keeping up with the changing weather.

The utility Hawaiian Electric is facing billions of dollars in liabilities amid allegations that negligent management of its grid fueled the Maui wildfire that killed 101 people last year. Northern California utility PG&E’s neglect of wildfire safety forced the company to plead guilty to 84 counts of manslaughter and pushed it into bankruptcy after its transmission line sparked the 2018 Camp Fire, which killed 85 people and destroyed nearly 19,000 homes and other buildings.

“We need to be honest with ourselves about what is the new normal,” said Joshua Rhodes, a research scientist at the University of Texas at Austin, speaking of this week’s Houston outages. “People right now are hot, and there are people dying. This was just a Category 1 storm. A Category 5 could hit us any time. We need to be better prepared.”

The headwinds to making timely upgrades can be intense. There are battles over who pays, a regulatory structure that does not always incentivize the most rational investments, and shareholder pressure to prioritize profits. Some activists and experts are quick to point out that CenterPoint managed to put together a $37 million pay package in 2021 for its former CEO while failing to make what they say are basic improvements for customers.

CenterPoint this year presented regulators with a sweeping, $2 billion “resiliency” plan aimed at shoring up the power grid against extreme weather. The plan, which calls for upgrading poles and wires, deploying technologies to reroute power when lines go down and burying some lines is lumbering through the approval process.

The upgrades, should regulators sign off on them, would take years to complete. The company and numerous stakeholders are battling right now over the cost of the plan and how much of it ratepayers should have to shoulder.

In the meantime, Houston-area residents are facing the prospect of more misery every time a storm rolls through.

About 2.3 million of CenterPoint Energy’s 2.6 million customers in the Houston area lost electricity during the latest storm.

In some of the low-income, multistory brick apartment complexes lining the road from the Interstate 45 to William P. Hobby Airport, residents — many of them immigrant workers — sought refuge Thursday on stoops, in open doorways and at the few minimarts that managed to open.

“The kitchen doesn’t function. We can’t eat,” said Dillon Moreda, 20, while charging his phone from a road sign outlet, something he learned to do while immigrating to Texas two years ago from Ecuador. The textile factory where he works was closed because of the outages, so he couldn’t afford to buy more food, he said. “No electricity, there’s no work, so no money.”

He was shocked to learn power may not return for another week. “A week?” he said. “So much time!”

Though cooling centers have opened across the region and the local bus authority will transport people to them free, Brian Murray, deputy emergency management coordinator for Harris County, said he worries there are some people out there stuck at home without power.

“We know there are residents in that situation; we just don’t know who they are or where they are,” he said. So far, the county had not received any reports of heat-related fatalities, he said. “We’re hoping we don’t.”

Outages were having major impacts across southeastern Texas, where 160 boil-water notices were in effect across eight counties, and 135 wastewater treatment plants were offline, according to Nim Kidd, chief of the Texas Division of Emergency Management. A dozen hospitals were under internal disasters, he said, the designation that means routine hospital operations are compromised.

The Houston region was under a heat advisory Thursday, with high temperatures forecast in the lower to mid-90s and humidity making it feel as much as 10 degrees hotter. Temperatures are forecast to approach the mid-90s each day for the next week, at least.

“This heat is especially dangerous if you remain without power and doing strenuous outdoor work,” the National Weather Service’s Houston forecast office warned. “Please stay hydrated and use safe generator practices.”

Harris County officials sent a wireless alert to residents Thursday urging them to be careful using portable generators after reports from fire stations about an uptick in calls related to possible carbon monoxide poisoning, Murray said.

Frustration with CenterPoint was mounting during what was just the latest electricity crisis — in May, an intense storm known as a derecho also caused about 1 million power outages, some of which took six days to restore.

“It appeared they were maybe not as prepared as they should have been,” Lt. Gov. Dan Patrick said at a Thursday news conference. “We’ll see what the facts are later.”