A teenage girl missing for more than a week and given up for dead by her family was found alive on the weekend in her wrecked car at the bottom of a ravine near Seattle.

Laura Hatch's survival was an "extraordinary tale," said police Sgt. John Urquhart. She had been missing since leaving a party on Oct. 2.

The Hatch family reported her missing when she didn't return from the party.

Laura Hatch's car at the bottom of an embankment in Redmond, Wash., Sunday. (AP photo)

On Sunday, searchers found her in the back seat of her wrecked Toyota Camry, hidden amid the trees – 61 metres down a ravine. Police had written off the 17-year-old as a runaway, and her family believed she was probably dead.

Doctors at Harborview Medical Center say Hatch likely survived because her severe dehydration kept a blood clot in her brain from growing. Her other injuries include broken facial bones.

Police said Hatch was speeding along a winding two-lane road after leaving the party, when her car went through a gap between guardrails and plunged down the ravine.

Efforts to find her were slowed initially because the teens at the party, where underage drinking had been taking place, were reluctant to tell police where it had been held.

Days later, detectives found out where the party had been and began to search for Hatch along her likely route home, issuing statewide bulletins and advisories.

On Saturday, Hatch's parents organized a volunteer search. That night Sha Nohr, a church member and mother of a friend of Hatch's, said she had dreams of a wooded area and heard the message, "Keep going, keep going."

Nohr said she and her daughter drove to the area where the crash occurred on Sunday, praying as she drove.

Nohr said something drew her to stop and climb over a concrete barrier and down almost 30 metres of a densely wooded slope, where she was barely able to see the wrecked Toyota Camry amid the trees.