Cross-country US storm causes blizzard warnings, tornadoes and two deaths

A destructive storm marched across the US on Wednesday, spawning tornadoes in Texas, Oklahoma and Louisiana, where the deaths of a young boy and his mother were reported, delivering blizzard-like conditions to the Great Plains and threatening more severe weather in the south.

The huge storm system was also expected to push more snow and ice into Appalachia and New England. The wintery blast dumped more than 2ft of snow in parts of South Dakota.

In Farmerville, Louisiana, about 90 miles east of Keithville, about 20 people were taken to the hospital, some with critical injuries, after a tornado caused major damage to mobile homes and an apartment complex, the Union parish sheriff said.

The Louisiana governor, John Bel Edwards, declared a state of emergency, saying initial reports indicated six possible tornadoes had hit the state in Caddo, Union, Rapides, Madison, East Carroll and Franklin parishes.

The forecast for Wednesday called for more severe storms and potentially additional tornadoes along the central Gulf coast, including New Orleans and southern Louisiana, Mississippi, Alabama and the Florida Panhandle.

Tornado warnings were issued on Wednesday morning for parts of Louisiana and Mississippi, where mobile homes at a park in Sharkey county were reduced to piles of debris. One resident, Leslie Jackson, told WLBT-TV her home at the Mason trailer park was one of only a couple left standing.

Five tornadoes were confirmed across north Texas on Tuesday afternoon, based on video and eyewitness reports, but potentially a dozen may have occurred, the National Weather Service (NWS) in Fort Worth, Texas, said.

Dozens of homes and businesses were damaged by thunderstorms and several people were injured in suburbs and counties north of the Dallas-Fort Worth area. More than 1,000 flights were delayed and more than 100 canceled, according to the tracking service FlightAware.

Photos sent by the city showed downed power lines on rain-soaked streets as well as toppled trees, damaged buildings and a semitrailer that appeared to have been tossed around a parking lot.

Forecasters expected the storm system to hobble the upper midwest with ice, rain and snow for days, as well as move into the north-east and central Appalachians.

In the Black Hills of western South Dakota, snow piled up to nearly 2ft in some mountainous communities.

Interstate 90, spanning western South Dakota, remained closed and the state department of transportation warned drivers to stay off highways in most of the state.

In North Dakota, accumulated snow caused authorities to shut down Interstate 94 between Bismarck and Fargo, the Bismarck Tribune reported.

Wet, heavy snow left tree limbs sagging and made driving treacherous in northern Minnesota on Wednesday, and a blizzard warning was issued for the north shore of Lake Superior. An NWS meteorologist, Ketzel Levens in Duluth, said snow had reached 6in to 8in in some parts.

The NWS issued a winter storm watch from Wednesday night through Friday afternoon, depending on the timing of the storm. Residents from West Virginia to Vermont were told to watch for a possible significant mix of snow, ice and sleet.