A woman vanished 16 days ago hiking in a Maui forest. Then a search helicopter made a pass.

Amanda Eller went missing in a Hawaii forest on 8 May. Photo / Javier Cantellops

Amanda Eller ventured into a dense forest in Hawaii on May 8, confident her 5km hike would finish so quickly that her phone and water were unnecessary. She left behind her wallet and her keys, hidden in her car's tire well for when she returned.

A physical therapist and yoga instructor who lives on Maui, Eller knew the terrain from a previous hike and veered off the trail for a quick rest.

But when she got up to resume, she was turned around, and in a quixotic search for the trail, Eller fractured her leg. She ate insects in the 16 days she was missing in the Makawao Forest Reserve - a disappearance that triggered a massive search drawing hundreds of volunteers, even after authorities scaled back their efforts early on.

Eller was found alive Friday, sunburned and smiling. A helicopter search team contracted by her family spotted her four miles from her car, gaunt after surviving on plants and water, a friend told KITV. She was airlifted to a hospital.

"She figured it out, she was smart, she was strong, she was prepared. We said that in the beginning and it was absolutely true," said her father John Eller, KITV reported.

Eller said his daughter "took a good fall," and got lost after looking for a way back, he told reporters outside a hospital in a video posted by Maui 24/7.

"They found her in a deep ravine, basically unable to get out, as I understand it," he said. "The rescuers had to be airlifted out as well, because it was so tumultuous."

Searchers Troy Helmer, Javier Cantellops and Chris Berquist spotted Eller from air foraging for food without shoes or socks.

"I've been looking at pictures of that girl 100 times a day. It was no mistake that it was her," Berquist said, KHON reported. "We were freaking out. We were trying not to trip over ourselves trying to get to her too fast."

Helmer told KHON that she was about 20 pounds underweight. Her father said she had abrasions and sun exposure but no broken bones. Photos posted to Facebook show her ankles swollen and legs covered in severe blisters.

Cantellops posted photos and videos of the search effort, gliding over canopies in a forest thick with creeks, ravines and brush that complicated search efforts. He took a photograph with Eller, eyes wide open and lips blistered.

"Amanda Eller you are one tough ass woman!!!" Cantellops wrote on Facebook. "We are all blown away at your barefoot resilience!!!"