The water reached her shoulders — and then she almost vanished” — Three little sisters miraculously survive the Camp Mystic flood. One counselor shattered a window. Another carried each child on their back. And a stormy night turned into a lesson about life, courage — and the quiet power of humanity. The Miller family thought they’d lost everything while half a world away. But then, a message arrived. Three names were spoken — and a camp whistle soaked in tears became a sacred keepsake. So… what really happened inside that final cabin, where the water licked the balcony’s edge? The story little Birdie, age 9, now tells — is leaving America breathless

Mom of 3 Says Her Youngest Daughter Was Hoisted Out of Shoulder-High Floodwaters by Camp Counselor (Exclusive)

“I can’t say enough about these heroic counselors,” Lisa Miller tells PEOPLE after the flooding tragedy

One Texas mom is speaking out after her three young daughters miraculously survived the deadly flooding at Camp Mystic.

Lisa Miller says she and her husband Nicholas were visiting France when they first heard that there had been “some flooding” at the camp. But Miller, a former counselor and camper, tells PEOPLE she initially didn’t think much of it.

As a counselor, she says she once spent a day stranded on a hill due to floodwaters — and that any flooding that happens is usually relatively minor, plus she knows there’s a protocol in place for what to do until the water recedes.

“It wasn’t until a friend texted and let me know that two girls from her youngest daughter’s cabin were found down [the Guadalupe River] that I realized something very catastrophic had occurred,” Miller says.

Although she didn’t initially hear anything from the camp staff — “they were consumed with the crisis at hand,” she says — when she texted camp director Mary Liz Eastland, the mom quickly learned that her daughters were accounted for, but that dozens of campers and an entire cabin were missing.

Also missing was the camp director’s father-in-law Richard “Dick” Eastland, who owned the camp — and was later found dead.

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories.

How her daughters, who were spending their second summer at Mystic together, managed to escape as floodwaters inundated the camp still baffles her.

Eliza, 14, had the most “typical” experience of a Mystic flood, the mom says. She was on “Senior Hill,” and her cabin just happened to be at the “highest point.”

“They were totally isolated from the rest of the camp,” she explains. “Their impression was it was just a very bad storm they were weathering together — at the time, it was a bit more of an adventure, or a crazy camp memory, than anything tragic. They were taking pictures and had no idea what was happening below.”

Meanwhile, Genevieve, 12, was in the very last cabin in an area known as “the flats.” Miller says one counselor ran to the camp office around 2 a.m. local time to let them know that their cabin was filling with water.

That alert prompted the camp to begin evacuating the cabins, with the camp owner even driving campers, including Genevieve, to safety at the Rec Hall. But water quickly began to pour into the building, so they moved to a balcony above.

“Water began rising quickly, coming so close to the balcony that they could touch it, and the waves were lapping just beneath them against the balcony,” the mom recalls. “The girls were scared, of course — I can’t say enough about these heroic counselors who had them singing camp songs and praying to keep them calm until the water receded, which it finally did.”

Miller’s youngest, 9-year-old Birdie, woke up at 2:30 a.m. that morning to the storm and couldn’t sleep, so she went to use the bathroom but noticed the water.

“Shortly thereafter, the counselors woke them up and had them put their things on the bed,” Miller says. “There was too much water outside the door to open it.”

After a counselor broke a window, each child was handed to the camp owner, who was there to help. As Birdie waited on the cabin porch for each girl to evacuate, she told her mom that the water reached her shoulders — and she was eventually hoisted onto another counselor’s back to get to safety.

Ultimately, all three girls were evacuated by Black Hawk helicopter to a reunification center and later reunited with Miller’s mom and stepdad as Miller and her husband were still out of town.

“I am still reeling,” she says. “The layers of this loss are unfathomable — the absolute heartbreak of the loss of these little girls, and their families’ sorrow, is of course paramount on all of our minds.”