A mother and her 8-year-old son were among the dead of at least three people as a destructive storm that sparked a tornado swept across the United States.
In the north, it brought blizzard-like conditions to the Great Plains and is expected to push more snow and ice into Appalachia and New England.
The frigid blast dumped more than two feet (60 centimeters) of snow in parts of South Dakota.
In the south, it produced some tornadoes.
Outside New Orleans, eight people were taken to hospital and a woman was found dead after a suspected tornado hit the Kerona neighborhood along the Mississippi River, damaging homes and throwing debris.
“There was debris everywhere. It was a horrible and very violent tornado,” Sheriff Greg Champagne said.
About 280 miles (450 kilometers) away in northern Louisiana, emergency services found the bodies of a mother and an 8-year-old boy who were reported missing after another tornado tore through their mobile home.
A steady stream of tornado warnings were issued for much of Louisiana, Mississippi and Alabama on Wednesday.
One plane landed in southwestern Louisiana, damaging several buildings on a hospital campus, and another in neighboring Mississippi, destroying four large chicken coops — one with 5,000 ovens.
Mobile homes in a nearby park were reduced to piles of debris.
Dozens of homes and businesses were also destroyed in Texas.
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At least five people were injured in the Dallas suburb of Grapevine, police said. A possible tornado ripped off the roof of the city’s municipal services center, with debris dangling from power lines.
More severe storms and more tornadoes are forecast for the Gulf Coast region, home to nearly 3 million people, from New Orleans to Mobile, Alabama, forecasts said.
More damaging weather is also forecast for the Florida Panhandle.
The icy weather from the massive storm is expected to affect the United States from coast to coast at some point, with snow and ice moving eastward in the coming days.
“What’s notable about this system is that it’s going to affect everything from California to the Northeast,” said Frank Pereira, a meteorologist with the National Weather Service in College Park, Maryland.