A harrowing video posted to Facebook captured the terrifying moments a woman filmed as the floodwaters surged past her house, seconds before she herself was swept to her death.

The 70-second clip shows Linda Almond, 55, trapped in her house in Waverly on Saturday as a torrent of murky brown water, several feet deep and carrying debris, rushes by outside.

“We are being flooded right now. Really scary,” Almond is heard to say. “Oh my goodness, oh my goodness!”

Another voice, presumed to be that of her son Tommy, 37, says he thinks something hit the side of the house. Moments later, Almond’s daughter Victoria told the Washington Post, the house “was lifted off its foundation” and the two were swept into the water.

Victoria Almond said her brother and mother held on to a utility pole but let go when they saw a house floating towards them. When her brother emerged after being pulled briefly under the water, she said, their mother was gone.

When she spoke to her brother on Saturday evening, “I could hear in his voice, the way he described it and his tone of voice” that her mother was dead, said Victoria Almond, who lives 45 miles from her sibling’s house.

“I already knew. It wasn’t confirmed, but I already knew.”

She added: “My brother went down for about 45 seconds underwater and when he came back up, he couldn’t find mom. That was when they let go. It was the last time he saw her.”

The storm brought 17in of rain in just three hours. Many scientists believe severe weather events such as the Tennessee floods, wildfires in western states and stronger and more frequent hurricanes in the US south and east are linked to the human-caused climate crisis.

Linda Almond is among 22 known victims of the flooding that swept through a rural part of Tennessee, destroying buildings and wrecking communities. Dozens are still missing.

Officials said on Tuesday about 120 homes were washed off foundations, destroyed or simply “gone”. The scope of the damage came into sharper focus as rescue teams continued to search.

Displaced residents found shelter with relatives, local churches and with housing provided by the American Red Cross. On Monday, Joe Biden declared a major disaster and ordered federal aid.

Local officials said those killed included babies and the elderly. Family members told reporters seven-month-old twins died after they were swept out of their parents’ arms.

Victoria Almond told the Post her mother, who was from south Florida, had been staying at her brother’s house 60 miles west of Nashville to save money after an expensive summer road trip with friends. Linda Almond was suffering from back problems but “was honestly happier than I had ever seen her”, her daughter told the Post.

Victoria Almond said watched her mother’s video on Saturday afternoon. It was posted at 10.13am.

“That was when the real worry hit,” she said.

She said she then spoke with an aunt, who had talked with her brother.

“She was crying and said that mom and Tommy were in danger and got caught in the flood,” Victoria Almond said.

Tommy Almond survived by climbing onto the roof of a wrecked building until the flood water receded.

“He really seems like he’s in shock,” his sister said. Her mother’s body was recovered on Sunday.