US storms kill at least 21 across 4 states on Memorial Day weekend

Tornado-spawning thunderstorms that swept the Southern Plains and the Ozark Mountains have killed at least 21 people across four US states as of Monday afternoon and wrecked hundreds of buildings, as forecasters warned of more severe weather.

The death toll over the three-day Memorial Day holiday weekend included at least eight fatalities in Arkansas, seven in Texas, four in Kentucky and two in Oklahoma, according to tallies by state emergency authorities.

A severe thunderstorm watch was issued for parts of New Jersey, New York and Pennsylvania until Monday evening, the National Weather Service said. The watch was in effect for more than 30 million people in the Northeast, as the storms were expected to move to that part of the East Coast.

Kentucky Governor Andy Beshear declared a state of emergency early on Monday. The weather service, opens new tab issued a severe thunderstorm watch for the Atlanta area and other parts of Georgia and for several western South Carolina counties until at least Monday afternoon.

"It was a tough night for our people," Beshear posted on social media platform X on Monday. He later said in a press briefing that devastating storms had hit almost the entire state. The storms damaged 100 state highways and roads, officials said.

At least seven people perished - including a 2-year-old and a 5-year-old from a family - and nearly 100 were injured on Saturday night when a powerful tornado struck communities in North Texas near the Oklahoma border, Governor Greg Abbott told a Sunday news conference.

Late on Sunday, Arkansas Governor Sarah Huckabee Sanders said at least eight people died in her state after the storms. An Arkansan suffering from chronic obstructive pulmonary disease died due to a lack of oxygen when the power went out.

President Joe Biden offered condolences for the lives lost when he spoke on Monday with Oklahoma Governor Kevin Stitt and Governors Abbott and Sanders, the White House said.

The Federal Emergency Management Agency was on the ground conducting damage assessments with state and local counterparts, the White House said, adding that Biden had directed federal agencies to provide support as needed.

Hundreds of thousands of Americans were without power on Monday due to the weather, according to the PowerOutage.US tracking website. In Kentucky alone, more than 160,000 customers lacked electricity.

In some areas, restoring power could take days, Kentucky Governor Beshear said in a news briefing.

The weather service warned that additional storms would move through the Ohio and Tennessee valleys, bringing damaging winds, large hail and more tornadoes, as well as heavy downpours capable of triggering flash floods.

The latest extreme weather came just days after a powerful tornado ripped through an Iowa town, killing four people, and more twisters touched down in Texas last week.

The US is preparing for what government forecasters have called a potentially "extraordinary" 2024 Atlantic hurricane season beginning next Saturday.