Teenager emerges from mountain forest three days after plane crash

A teenager whose small plane went down in the North West US on Saturday has emerged from the forest after walking from the crash site through rugged mountain forests.

Autumn Veatch, 16, was flying with her step-grandparents, Leland and Sharon Bowman, aged 62 and 63, from Montana to Lynden in Washington State but the plane never reached its destination.

Search and rescue crews have been searching the thick forests of the Cascade Range where the plane was believed to have crashed.

Autumn managed to follow streams and creeks down the mountains till she found a trail pass which she followed to a nearby highway and waited until some passing hikers picked her up on Monday afternoon.

She was driven to a nearby store in the town of Mazama where workers called the local sheriff.

"She basically related the story what happened, out walking for the past few days and got to Highway 20 and waited for the first people to come by," Rick Leduc of the Mazama Store told King 5 News.

"It sounds like she just followed a drainage out and just continued (along) the streams and rivers getting larger.

"It's pretty miraculous she was able to do what she did. It's pretty rugged country ... probably some of the harshest country in the Cascades."

Autumn was taken to hospital and treated for non-life threatening injuries and is reportedly doing well.

There is no word yet on the exact location of the downed plane or the condition of Autumn's grandparents.

Okanogan County Sheriff Frank Rogers to the Associated Press: "We're not going into the status of the grandparents. She was the only one who walked out.".

Using new information provided by Autumn, the search continues with two planes — one aircraft scanning the area with specialised equipment, the other using low-altitude visual surveillance.