Those power outages in Fort Worth and North Texas? Expect them to continue Tuesday.

Texans may be without electricity at times through Tuesday, as freezing temperatures continue across the state.

On Sunday night, the Electric Reliability Council of Texas — the group that manages Texas’ flow of electricity — saw peak winter demand for electricity, leading to rolling outages across the state.

But for some, those outages spanned hours or even all day, leaving people wondering when power would return.

”These outages will continue until there’s sufficient generation being able to be brought back online to meet demand on the system,” Dan Woodfin, ERCOT’s senior director of system operations, said Monday. “At this time, we anticipate that we’ll need to continue these controlled outages at some level for the rest of the day and at least the first part of tomorrow — perhaps all day tomorrow.”

Gov. Greg Abbott announced Monday that the state was sending “maximum resources” to local officials to help clear roadways and assist essential workers, such as health care professionals and power grid workers. He’s also sending out the Texas National Guard for welfare checks and to help people get to warming centers across the state.

Abbott said ERCOT and the Public Utility Commission are “working non-stop” to restore electricity.

“Due to the severe weather and freezing temperatures across our state, many power companies have been unable to generate power, whether it’s from coal, natural gas, or wind power,” Abbott said in a prepared statement.

Abbott later tweeted that hundreds of thousands of Texans were in the process of having their power restored.

At about 5 p.m. Monday, Oncor said there were more than 11,000 outages affecting more than a million customers in Texas.

“ERCOT and Texas electric companies have been able to restore service to hundreds of thousands of households today, but we know there are many people who are still waiting,” said ERCOT President and CEO Bill Magness in a prepared statement. “It’s also important to remember that severe weather, mainly frigid temperatures, is expected to continue, so we’re not out of the woods.”

The widespread outages prompted the Texas Democratic Party to criticize Abbott for what the Democrats said was a failure to manage crisis situations and plan ahead.

“There is no reason at all that Texas — a state that produces the most energy in the country — has millions of people without power. Abbott’s inability to govern is not only negligent but incredibly dangerous,” said Texas Democratic Party Chairman Gilberto Hinojosa in a prepared statement.

Woodfin, of ERCOT, described the chain of events that led up to the outages during a Monday call with reporters. The call’s audio was recorded by WFAA.

Headed into Sunday afternoon, ERCOT’s main concerns were high demand for electricity, loss of generation due to gas supply and icing on wind turbine blades, Woodfin said. Around 11 p.m. that night, generating units began going offline due to the cold weather, leading to diminishing reserves of electricity.

ERCOT implemented its emergency operations plan, which allows it to use additional resources for emergency situations. Demand continued, prompting the controlled outages.

”If we don’t have more supply, the only thing we can do is start to reduce demand on the system,” he said.

Many residents of the state, including North Texans, reported outages spanning several hours or even all day. Typically these would be done on a rolling basis. But some providers were unable to rotate outages because of the “quantity of outage that has been needed,” Woodfill said.

”They just don’t have enough options that don’t have critical facilities like hospitals or emergency responders,” he said.

Most of the generators that went offline overnight were thermal generators, fueled by gas, coal or nuclear power, but the reason why they went offline remains unclear, Woodfill said.

Asked whether ERCOT’s emergency plan was inadequate, Woodfin said the plan has worked. He later noted that a weather event like the one seen thus far is “unprecedented.”

“We have tried to work with the generators to develop these best practices for winterization,” he said. “They have been put in place, but this event was well beyond, kind of, the design parameters for a typical, or even an extreme, Texas winter that you would normally plan for. Really, the result is what we’re seeing today.”

U.S. Rep. Michael Burgess expressed concern about the outages amid dropping temperatures.

”I am working to understand why this happened, what is being done to get the power back on in our communities, and how this can be prevented in the future,” he said on Twitter.

State Rep. Giovanni Capriglione indicated he was disappointed with the communication from ERCOT.

”I understand that (ERCOT) has a tough job right now, but they really should be doing a better job communicating to all the Texans who are freezing in their homes,” he said.