Image copyright Instagram Image caption Autumn Veatch posted a picture of herself aboard a plane on her Instagram account on Saturday

A 16-year-old girl has been found after hiking to safety from the scene of a plane crash in a mountainous area of the north-western US.

Autumn Veatch had been on a small plane with her step-grandparents which crashed in the North Cascades National Park in Washington state.

She is being treated in hospital, but has no life-threatening injuries.

It is not known what happened to Autumn's step-grandparents, whom she attempted to pull from the wreckage.

Autumn's father, David, told reporters outside a hospital in the town of Brewster that his daughter was exhausted, but doing remarkably well.

He said she was able to joke with him about all the survival shows they watched together on television, according to the Associated Press news agency.

"She's just an amazing kid,'' he said. "There's more to her than she knows.''

'It's a miracle'

Transport authorities said the Beech A-35, which was registered to Autumn's step-grandfather, left Kalispell in Montana at around 13:00 on Saturday.

It was due to land in Lynden, Washington, later on Saturday and family members raised the alarm when there was no sign of the plane.

Media playback is unsupported on your device Media caption In a 911 call, Autumn described her injuries and confirmed that she was the only survivor

Autumn left the scene of the crash after a day and followed the river, via a trail, downstream to the nearest road, family friend Santina Lampman told the Seattle Times.

A passing motorist spotted her on Monday and took her to the town of Mazama, where she received medical attention before being taken to hospital.

Doctors say she is suffering from dehydration and a treatable kind of muscle tissue breakdown caused by exercise without food or water, but that she is expected to make a full recovery.

"It's a miracle, no question about it," Lt Col Jeffrey Lustick of the Civil Air Patrol told reporters. "Moments of joy like this can be hard to find."

The plane's wreckage has not yet been found but the search was due to resume again on Tuesday.