Rescuers found the mother shortly after, about a mile downstream from the SUV. Her children were nowhere to be found.
"She had wrapped her arms around them, and the water just took them away," the mother's sister, Tina Westlin, told The Washington Post earlier.
Damien was found Monday, two days later, a little more than 5kms from where the SUV stalled, according to the Madison County Sheriff's Office. Krystal's body was found 16km away.
Kelly Laird, a relative of the family, said the thought of never finding Krystal haunted loved ones for days.
"They're relieved that the children will be able to be buried together and laid to rest together," Laird said yesterday. "The best thing is that they're found, that they're together and there's no one who's been left behind."
Laird said the children's family attended a memorial at Huntsville High School's football field on Saturday. Shortly after, authorities notified them that Krystal had been found.
"We're saddened, you know, that this tragedy went on," Laird said. "But weight has been lifted off of her shoulder not knowing where her daughter was."
Authorities said earlier that they're not publicly identifying the 38-year-old mother while the search was ongoing to give her space to grieve. It was not clear yesterday whether that has changed. Madison County Sheriff Rick Evans did not return a call from The Post.
More than 200 volunteers helped in the search efforts, authorities said. Many showed up with their horses, ATVs and canoes. A farm crop sprayer from Illinois flew his helicopter to help with the search. Government agencies from neighbouring states sent search dogs, while nearby schools and churches trucked in food.
Laird said even a woman who is seven months pregnant showed up.
She said the children's funeral is scheduled for today.
"We just want to make sure that they're not ever forgotten," she said.