Tornado causes havoc in Texas as record-breaking heat wave looms

A tornado ripped through central Texas on Wednesday evening, causing huge damage and destroying homes, as forecasters warn of a potentially record-breaking heat wave in the state.

The city of Temple, northeast of Austin, declared a state of emergency and opened a shelter for displaced people after a twister caused widespread devastation.

Cars were overturned, power lines destroyed and entire buildings toppled in Temple, according to images published by NBC affiliate KXAN of Austin. There were no reports of deaths or injuries there or in the wider Bell County area, which was also hit by severe thunderstorms.

Footage posted on social media shows buildings in Temple and nearby Belton missing roofs, piles of rubble and smashed windows.

Flood warnings were in place Thursday morning for much of northern Texas, including Dallas and Forth Worth, along with parts of Oklahoma.

Severe weather continues for a huge portion of the United States on Thursday, with warnings in place for 23 million people from Texas to North Dakota and New England. Omaha, Nebraska, is at particular risk and could face tornadoes, winds of more than 75 mph and hail measuring more than 2 inches across.

And there is no let-up on Friday: A previously mild forecast has been upgraded to put storm warnings in place for 37 million people from Dallas to Chicago. Large hail will particularly become a threat in the Southern Plains region.

More than 110,000 energy customers were without power as of 6 a.m. Thursday, as well as almost 20,000 in Louisiana, according to the energy connection tracking website PowerOutage.us.

The destructive weather comes as Texas faces a heat wave that could break 100-year-old records: the National Weather Service said the south of the state could see temperatures of more than 115 degrees over the weekend. The record high for Austin in May is 104, recorded in 1925.

"Record or near-record warm overnight temperatures will provide little to no relief to those without adequate or reliable cooling," the agency said in a forecast early Thursday.

Severe heat warnings were in place for hundreds of thousands of people across southern Texas from 1 p.m. to 7 p.m. local time (2 p.m. to 8 p.m. ET).

"Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances," the weather service office covering Austin and San Antonio warned.

In a chaotic week in an extraordinary tornado season, at least four people have been confirmed dead as a result of extreme weather in Iowa, as a tornado devastated the town of Greenfield.