Officials in Texas say two people are dead likely because of the subfreezing temperatures that have caused massive power outages across the state. More bad weather, including freezing rain, was expected Tuesday night.
From frozen natural gas wells to frozen wind turbines, all sources of power generation have faced difficulties during the winter storm.
The breakdown sparked growing outrage and demands for answers over how Texas - whose Republican leaders as recently as a year ago taunted California over the Democratic-led state's rolling blackouts - failed such a massive test of a major point of state pride: energy independence.
"We are very angry".
Upgrading equipment to withstand extremely low temperatures and other changes, such as providing incentives for customers to conserve power or upgrade to smart appliances, could help avoid disasters like this one, said Le Xie, a professor of Electrical and Computer Engineering at Texas A&M University and assistant director of energy digitization at A&M's Energy Institute. "We're all angry because there is no reason to leave entire neighborhoods freezing to death".
"The sky lit up and there was a lot of pop-pop-popping" and thunder, she said.
The toll of the outages was causing increasing worry. Other causes included auto crashes and carbon monoxide poisoning.
At least 21 people have died in Texas, Louisiana, Kentucky, and Missouri including four killed in a house fire in Sugar Land, Texas, where the power was out, according to police and local media.
On Sunday, there were almost 120 auto accidents in Houston alone, while on Thursday, icy roads led to a massive crash involving more than 100 vehicles in Fort Worth, killing six people and leaving dozens more needing hospital treatment.
The privately-owned Electric Reliability Council of Texas has not provided a clear timeline either. "It's priority number one!" "The ability of some companies that generate the power has been frozen", Governor Greg Abbott wrote on Twitter.
Blackouts lasting more than an hour began around dawn Tuesday for Oklahoma City and more than a dozen other communities, stopping electric-powered space heaters, furnaces and lights just as temperatures hovered around minus 8 degrees (minus 22 degrees Celsius).
By some estimates, almost half of the state's natural gas production has screeched to a halt due to the extremely low temperatures, while freezing components at natural gas-fired power plants have forced some operators to shut down.
The PowerOutage.us website, which tracks power outages, said 4 113 701 Texas customers were experiencing outages at 02:05 (07:05 GMT) on Tuesday.
At least 10 deaths have been linked to the recent bad weather, and authorities across the U.S. urged residents to exercise caution in navigating the perilous conditions.
"It's critically, critically important to get the power restored as quickly as possible". The Federal Emergency Management Agency said Texas had requested 60 generators and that hospitals and nursing homes would get priority.
Thirty-five warming shelters were opened to accommodate more than 1,000 people around the state, FEMA said during a briefing. But even they weren't spared from the outages, as Houston was forced to close two on Monday because of a loss in power.
On Tuesday, ERCOT also asked Austin Energy to shed more power and shut off more facilities, according to KXAN. In Texas, demand peaks in August, at the height of the state's sweltering summers.
He rejected that the storm went beyond what ERCOT could have anticipated.
"That's nonsense. It's not acceptable", Hirs said. "This is not a surprise".
The Lone Star State accounted for more than half of the fatal cases reported so far, as residents dealt with bitter cold temperatures not seen in decades.
"We're going to have to plan for more of this kind of weather".