Millions of people in the US state of Texas have woken without heating again, as power failures continued to plague the state following a historic winter storm that has killed 21 people so far.
Four of those deaths were from one family, who perished in a house fire while using a fireplace to stay warm in Houston. Other causes included car crashes and carbon monoxide poisoning.
Over four million people across the state were without power as of late Tuesday, including 1.4 million people in the Houston metropolitan area. A quarter of homes in Dallas were dark.
Houston's temperatures have fallen below zero in recent nights, with -3 degrees forecast for both Thursday and Friday nights.
Photos show families huddling together under blankets in their homes to stay warm, while the less fortunate head to shelters for warmth. Huge queues have been forming for hundreds of metres outside supermarkets.
The storm has impacted four states, and the cold is not expected to let up until this weekend.
The weather has shuttered Covid-19 inoculation centres and hindered vaccine supplies.
Governor demands answers over blackout
Texas Governor Greg Abbott and other top officials in the state, the country's second largest, are demanding answers from operators and leaders at the Electric Reliability Council of Texas (Ercot), an energy cooperative responsible for 90 per cent of the state's electricity.
"We knew a week in advance this storm was coming," Mr Abbott said during an interview on KLBK television.
"Ercot should have had a backup plan."
Lina Hidalgo, the top executive in Harris County, which encompasses Houston, warned residents to brace for prolonged problems.
"Let me give it to you straight," she wrote on Twitter on Tuesday night. "There's a possibility of power outages even beyond the length of this storm."
Mr Abbott demanded that state lawmakers investigate what went wrong and pass reforms to the Electric Reliability Council of Texas, which oversees the electricity grid.
The storm has knocked about a third of the state's generating capacity offline. The power grid in Texas relies heavily on natural gas, responsible for nearly half the electricity generated.
President Joe Biden assured the governors of states hit hard by storms that the federal government stands ready to offer any emergency resources needed, the White House said in a statement.
Storms dumped snow and ice from Ohio to the Rio Grande through the long Presidents Day holiday weekend, and treacherous weather was expected to grip much of the United States through Friday.
- with AP
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