A 52-year-old climber who was injured Saturday when she fell off a rock-face onto her back at Robert Louis Stevenson State Park in Napa County had to be rescued from the area at the end of a cable by the Sonoma County sheriff's helicopter, authorities said.

The unidentified woman fell about 15 feet while practicing rappelling with others at Mount St. Helena. But she was at the bottom of a cliff about 175 feet high, sheriff's officials said.

The crew aboard the helicopter, known as Henry 1, responded to the 1:05 p.m. call. Arriving in the area, the helicopter landed, and crew members equipped the aircraft with a 200-foot-long rescue line.

The pilot used the line to lower a sheriff's deputy and a paramedic to the woman so she could be assessed and stabilized.

Fellow climbers helped the crew immobilize her and package her in a kind of basket so she could be extracted from the area at the end of the line, authorities said.

She was flown to an area where the helicopter could land and the patient and crew could be brought on board, they said.

The woman was taken to Queen of the Valley Hospital in Napa, landing just more than an hour after her fall was reported, officials said.