A 48-year-old West Hempfield Township woman was seriously injured Sunday morning when she plummeted about 100 feet off Chickies Rock, investigators said.

The woman, whose name wasn't released, was on a hike when she fell into a ravine at the base of the rock, police said.

West Hempfield Township Police Chief Mark Pugliese said Monday that investigators believe the woman was hiking solo.

She drove to the park Sunday morning in a green Nissan Altima, which police found in a parking lot.

Based on where she was found and the nature of her injuries — which Pugliese called "serious" — the woman likely fell from the summit.

Two local hikers were on a trail in the park when they heard faint moans from the ravine just after 11 a.m., police said. They looked into the ravine, realized the woman was seriously hurt and called 911.

A medical helicopter flew the woman to Lancaster General Hospital, where she was admitted to the trauma unit.

Because her name was not released, her condition could not be learned.

The woman's family told police the injuries were serious. "They are still hopeful that she'll recover," the chief said.

There is nothing to indicate foul play, Pugliese said, but police are asking anyone who may have seen the woman Sunday to call them at 285-5191.

Pugliese said accidents on the rock have decreased since the county built a split-rail fence around the summit in 1990.

"Prior to the fence, it was once or twice a year," the chief said.

Newspaper archives show 12 people have died from falls there since 1981 — eight of those between 1981 and 1990.

Four deaths at Chickies Rock have been reported since the fence was built, according to newspaper records. The most recent death was in November 2006, when a York County teenager fell while watching trains.

The rock offers a view of the Susquehanna River, York County and the borough of Marietta.

E-mail: bhambright@lnpnews.com