At least 19 people have died in a vast storm system that kicked up apparent tornadoes, shredded mobile homes and left other destruction scattered around the south-eastern US.

Authorities said on Monday at least 15 deaths occurred in south Georgia, including seven from an apparent winter twister that tore through a trailer park before dawn on Sunday. Authorities reported four deaths on Saturday in Mississippi as the storm system ramped up. It was so big parts of it threatened the Carolinas and north Florida.

In south-west Georgia, Bridget Simmons, along with her parents, her daughter and her grandson, were in their brick home in the city of Albany when the sky went dark on Sunday afternoon and the wind began to howl.

“I was in the den and I heard that loud roar and I grabbed the baby and I said, ‘Let’s go, guys. This is it.’ We laid down and that was it.” The wind was so loud, she added, “you could hear it beating back and forth”.

Minutes later, their home was largely unscathed, save for a carport that collapsed atop two cars. But trees were down all around, police sirens wailed and authorities would add four more deaths for an overall count of at least 19.

Some 60 miles away, coroner Tim Purvis in south Georgia’s Cook County confirmed seven people had died at the mobile home park in the rural community of Adel, where about half of the 40 homes were leveled. Debris lay about not far from mobile homes largely untouched but emptied of survivors and cordoned off by police.

Elsewhere, shredded siding from mobile homes, a house stripped of exterior walls but left standing, and even a piano blown outdoors all bore evidence of the power of the storm system that tore across the deep south.

In South Carolina, the National Weather Service confirmed that two tornadoes had struck over the weekend, injuring one woman who was trapped in a mobile home that was damaged near Blackville. The weather service says a tornado touched down at about 3.45pm on Saturday in Barnwell County and moved into Bamberg County. The other occurred in Orangeburg County a few minutes later.

Weather experts say tornadoes can hit any time of year in the south – including in the dead of winter.

While the central US has a fairly defined tornado season – the spring – the risk of tornadoes “never really goes to zero” for most of the year in the south-east, said Patrick Marsh of the Storm Prediction Center in Norman, Oklahoma.

He said 39 possible tornadoes were reported across the south-east from early Saturday into Sunday evening – none immediately confirmed. Of those, 30 were reported in Georgia, four in Mississippi, and one each in Louisiana and South Carolina.

January tornado outbreaks are rare but not unprecedented, particularly in the south. Data from the Storm Prediction Center shows that over the past decade the country has seen an average of 38 tornadoes in January, ranging from a high of 84 in 2008 to just four in 2014.

Nineteen-year-old Jenny Bullard said she and her parents, Jeff and Carla, were glad to have escaped without major injury after an apparent tornado battered their home in Cook County. They are a farming family dating back generations, living not far from where the mobile homes were destroyed.

The middle section of their brick house was blown off the slab, leaving nothing but the kitchen island standing. On one side, the parents’ bedroom remained intact. Jenny’s bedroom on the other side was smashed in and a piano was blown out of the house.

She recalled awaking to the sound of hail before dawn.

“The hall wall came in on me and I fell down. And our backdoor came through and fell in on me. And I heard my dad calling my name … There was a bunch of stuff on top of him and I just started throwing everything I could until I got to him,” she said.

Together, she and her father met up with their mother and got free. The young woman wore a sling on one arm hours afterwards on Sunday as she went back through the debris for belongings. Bricks lay scattered about, alongside their possessions and furniture.

“The first thing I wanted to do was get all the pictures,” she said. Across the street, where the Bullards kept farm equipment in sheds, one shed was blown in amid twisted metal. Two grain silos were blown over.

“It’s a horrible tragedy. But all this stuff can be replaced,” she said. “We can’t replace each other. We’re extremely lucky. My dad is lucky to be alive.”