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With approximately 1.2 million residents in the Houston area without power, a Texas official slammed the company that runs the electric grid, saying: “The bottom line this evening is, we’re in for another long night.”

The National Weather Service office in Houston was predicting rain and freezing rain Tuesday night with temperatures in the 20s.

Harris County Judge Lena Hidalgo said it has been a natural disaster and a man-made one as well. She was one of several officials from the state calling for answers from the Electric Reliability Council of Texas, a grid operator that controls about 90% of the state’s electric load.

“Every night since this started, we’ve seen less generation, not more,” Hidalgo said. “So, let me give it to you straight based on the visibility I have – whether you have power or not right now, there is a possibility of power outages even beyond the length of this weather.”

About 3.3 million homes and businesses were without power in Texas on Tuesday evening as a result of freezing temperatures and a deadly winter storm that swept into the state early this week. The entire state saw temperatures below freezing during at least parts of Monday and Tuesday, and utilities have been knocked out or frozen over by the bitter cold – leaving many without primary means of heating their homes.

LIVE UPDATES: Millions without power as US braces for another winter storm

ERCOT said it expected to restore electricity service to some customers Tuesday afternoon, but “the amount we restore will depend on how much generation is actually able to come online.”

ERCOT CEO Bill Magness said his company averted a total disaster.

“I think from the perspective of the grid collapsing, I think what has happened here is a response that kept the grid from collapsing, that kept us from going into a blackout condition,” he said. “Now the difficulties that this has imposed on the citizens of Texas, everybody in the state, have been enormous.”

Gov. Greg Abbott, Lt. Gov. Dan Patrick, US Rep. Sheila Jackson Lee and the Texas speaker of the house were among those calling for a look into how ERCOT dealt with the storm.

Abbott said he wants an investigation and swift reform of the system.

“The Electric Reliability Council of Texas has been anything but reliable over the past 48 hours,” Abbott said in a statement. “Far too many Texans are without power and heat for their homes as our state faces freezing temperatures and severe winter weather. This is unacceptable.”

Responding to the governor, Magness said the company sees the need for an investigation.

“Electricity is an essential service,” said Magness. “As we do the event analysis after this is over, once we get through the emergency and we get customers back on, we want to participate in that, we want to learn lessons, because if, you know, there’s mistakes that we can be correcting, you want to find them, and we want to put the processes in to correct them.”

Galveston County Judge Mark Henry said ERCOT officials were less than forthcoming with information ahead of the deadly storm that has left much of his county battling power outages and freezing temperatures.

“We were told Sunday afternoon in a message that there’ll be rolling blackouts, about up to an hour off, and then up to three to four hours on,” he said. “That was fine. That didn’t happen. The power went off, it stayed off. We had no rolling blackouts at all in this county.”

He said county officials would have made different decisions, including calling for people to evacuate, if they had been told the power was going to stay off.

Three die in carbon monoxide incidents

Frigid temperatures and widespread power outages plagued swaths of Texas for the third straight day Tuesday, sending numerous residents to vehicles, fireplaces and shelters in desperate search of warmth.

In the town of Nevada outside Dallas, Clint Cash said he’s resorted to living in his car parked in an open area outside his home, which had largely been without power since Sunday evening when temperatures dipped into the teens.

“I’m wearing several layers of clothes to keep my body warm” and using heat from his vehicle, Cash, 44, told CNN affiliate KTVT on Monday.

The cold is believed to have contributed to at least three deaths in the Houston area alone, police said. That includes a woman and a girl who died of carbon monoxide poisoning after a car was running in the garage at their home to create heat because the power was out, Houston police said Tuesday morning.

Another person died in Fort Worth from a carbon monoxide incident, according to fire officials there.

The Harris County fire marshal’s office, meanwhile, has reports that more than 50 people have suffered carbon monoxide poisoning relating to heating issues during the cold spell, Hidalgo said.

Treacherous weather conditions have led to more than 550 car crashes in the area since Sunday, Houston Police Chief Art Acevedo said.

“Our roadways are still very icy. Please avoid traveling unless absolutely necessary,” Acevedo said on Twitter.

Huge electricity demand

Officials have said some utilities’ ability to generate the power has been frozen – including natural gas and coal generators. said intentional, rolling power blackouts will happen in parts of the state to balance huge demand with struggling supply.

Temperatures are expected to be below freezing throughout Tuesday in roughly the state’s northern half, and they may just reach above it in Houston and San Antonio, according to a National Weather Service forecast.

While snow has fallen across much of Texas, more snow and ice are expected for much of the state through Wednesday as part of a larger storm system.

Up to 6 more inches of snow could fall in the Dallas/Fort Worth area, while freezing rain is forecast for Austin, San Antonio and Houston.

“We’re looking at some more rain and sleet tonight,” San Antonio Fire Chief Charles Hood said. “This could be the worst night as far as temperature.”

Hood said his department has had a rough week with the storm, “We had 2,608 calls for service yesterday. We did about four times the number of calls we do on a normal day.”

A truck braves the frozen roads in Houston on Monday, February 15.

Relying on fireplaces and generators

Barbara Martinez had a mission Tuesday that she wouldn’t normally undertake: find more wood for the fireplace that has become her home’s main source of heat in freezing weather.

Her home in the Houston suburb of Jersey Village has been largely without power since Sunday at 3 a.m., she told CNN.

She, her elderly parents, and her two dogs have been huddled together in one room with a fireplace.

“We have several layers of clothing and it’s cold,” Martinez said. “We’ve been using our cars to charge up phones, and (the) signal here is nearly impossible to use.”

“We hope the power comes back soon because we are running out of firewood,” she said. “My goal today is to find more firewood.”

Barbara Martinez's father sits in front of the fireplace at her home in a Houston suburb.

In the Fort Worth suburb of Watauga, Elijah Dorminy’s family has depended on their generator to make it through the deadly cold – and he fears that soon even that won’t be an option.

Dorminy, his wife and their four children were worried what will happen when they need to refill their generator with gas again. Only one gas station still had fuel in Watauga, Dorminy told CNN on Monday evening.

“Pray for us, this is going to be rough,” he told CNN.

Water shut off in Abilene, and cell phone service interrupted outside Houston

The city of Abilene said it was forced to shut off water service Monday evening because of a power outage at three water treatment plants.

The city of about 120,000 people is about a 150-mile drive west of Fort Worth.

Power has since been restored to one water plant and crews are working toward the goal of restoring service to most of the city by day’s end Tuesday, officials said.

When service is restored, a boil water notice will be in effect, and customers should bring water to a vigorous boil for at least two minutes before consumption, according to the statement.

“Texans with electricity are asked to conserve as much as possible in an effort to relieve the demand on the state’s power grid and help restore service,” the city said.

In Waco, Mayor Dillon Meek said the city would rent 15 hotel rooms for homeless people.

Covid-19 vaccines and appointments at risk

The storm has complicated Covid-19 vaccinations, causing appointments to be postponed and threatening supplies.

No first-dose vaccines were being shipped to the Corpus Christi-Nueces County Public Health District on Monday and Tuesday because of winter weather, according to a news release.

San Antonio postponed vaccine appointments scheduled for the Alamodome stadium until Saturday, according to a news release from the city.

“With the current icy conditions expected to remain until at least tomorrow, we want to ensure the safety of the public. We also want to remind the public who may be concerned about the small delay for their second dose, that we are still within CDC guidelines to ensure the vaccine will still work with no issues,” the release stated.

After power was lost at the Harris County Public Health building and backup generators failed, officials had to race to allocate and save 8,400 vaccines before they spoiled, Hidalgo, the county judge, said Monday.

Harris County officials settled on Houston’s Ben Taub, Lyndon B. Johnson and Houston Methodist Hospitals, as well as Rice University and the Harris County Jail as the locations to receive the vaccine overnight, Hidalgo said.

CNN’s Dave Alsup, Andy Rose, Alisha Ebrahimji, Keith Allen, Gregory Lemos, Jeremy Grisham, Carma Hassan, Amanda Jackson, Ed Lavandera, Rebekah Riess and Amir Vera contributed to this report.