A story about the “miraculous” survival of two girls in the catastrophic Texas floods has been revealed as a cruel hoax – as the deadly toll climbs even further.

The toll from the horror flash floods reached 82 on Sunday (local time), including at least 28 children.

Dozens of people are still missing, including girls from a summer camp, as the desperate search enters a third day, and warnings of more rain and flash flooding prompted fresh evacuations.

On Sunday, a rare survival story apparently emerged, with the local Kerr County Lead newspaper reporting that two young girls had been rescued from more than eight metres up a tree in Comfort, Texas, more than 48 hours after the catastrophic flash flooding.

The story was sourced to social media reports from volunteers exclaiming the rescue and picked up across local, national and international media.

But it was retracted shortly after, when local sheriff Larry Leitha said it was“100% inaccurate”.

Kerr County Lead editor Louis Amestoy said the false story was disappointing but emphasised the challenges during rapidly evolving natural disasters.

“Like everyone, we wanted this story to be true, but it’s a classic tale of misinformation that consumes all of us during a natural disaster. Unfortunately, the story is not true and we are retracting it,” Amestoy said on Sunday (US time).

Also on Sunday, Leitha said 68 people had died in flooding in Kerr County, the epicentre of the flooding, among them 28 children.

Texas Governor Greg Abbott said another 10 had died elsewhere in Texas and 41 were confirmed missing.

Among the most devastating impacts of the flooding occurred at Camp Mystic summer camp, a nearly century-old Christian girls camp. There were 700 girls at the camp when the floods hit – and Leitha said on Sunday that 10 campers and a counsellor were still missing.

“It was nothing short of horrific to see what those young children went through,” said Abbott, who said he toured the area on Saturday and pledged to continue efforts to locate the missing.

There are reports that the owner of Camp Mystic, Dick Eastland, is among the dead. His grandson shared an Instagram tribute on Saturday, saying Eastland had been trying to rescue campers.

“If he wasn’t going to die of natural causes, this was the only other way – saving the girls that he so loved and cared for,” George Eastland wrote.

“That’s the kind of man my grandfather was. He was a husband, father, grandfather, and a mentor to thousands of young women. Although he no longer walks this Earth, his impact will never fade in the lives he touched.”

A Camp Mystic employee, Glenn Juenke, told CNN Eastland died “remaining a true hero until the very end.”

“Eastland tragically lost his life while courageously attempting to save several young children,” Juenke said.

The flooding occurred after the nearby Guadalupe River broke its banks after torrential rain in the central Texas area on Friday, the US Independence Day holiday.

Texas Division of Emergency Management Chief Nim Kidd said on Sunday the destruction killed three people in Burnet County, one in Tom Green County, five in Travis County and one in Williamson County.

“You will see the death toll rise today and tomorrow,” Texas Department of Public Safety director Freeman Martin said.

Officials said on Saturday that more than 850 people had been rescued, including some clinging to trees, after a sudden storm dumped up to 380 millimetres of rain across the region, about 140 kilometres north-west of San Antonio.

“Everyone in the community is hurting,” Leitha said.

Kidd said he was receiving unconfirmed reports of “an additional wall of water” in some creeks in the Guadalupe Rivershed, as rain continued to fall on already saturated soil in the region.

He said aircraft were scouting for additional floodwaters, while rescuers who might be in harm’s way had been alerted to pull back from the river.

The US National Weather Service issued flood warnings and advisories for central Texas as more rain fell, potentially complicating rescue efforts.

The Federal Emergency Management Agency was activated on Sunday and is deploying resources to first responders in Texas after President Donald Trump issued a major disaster declaration, the Department of Homeland Security said.

US Coast Guard helicopters and planes are helping the search and rescue efforts, the department said.

Trump said on Sunday he would visit the disaster scene, probably on Friday. He has previously outlined plans to scale back the federal government’s role in responding to natural disasters, leaving states to shoulder more of the burden themselves.

Some experts questioned whether cuts to the federal workforce by the Trump administration, including to the agency that oversees the National Weather Service, led to a failure by officials to accurately predict the severity of the floods and issue appropriate warnings ahead of the storm.

The disaster unfolded rapidly on Friday morning as heavier-than-forecast rain drove river waters rapidly to as high as 9m.

A day after the disaster struck, the summer camp was a scene of devastation.

Inside one cabin, mud lines indicating how high the water had risen were at least 1.83m from the floor. Bed frames, mattresses and personal belongings caked with mud were scattered inside. Some buildings had broken windows, one had a missing wall.

Lifeline 131 114

Kids Helpline 1800 55 1800 (for people aged 5 to 25)

-with AAP