Yellowstone National Park, Wyo. ? A woman lost her footing while taking a photograph and fell 500 feet to her death in a canyon.

Deb Chamberlin, 52, of Rockford, Mich., was visiting the park with her husband and two children. She stepped over a retaining wall to take a photograph.

Her husband flagged down a passing motorist, who called 911 after the Saturday morning accident at an overlook along the Yellowstone River, park officials said.

A ranger rappelled down the canyon wall to reach the woman, but she was dead at the scene.

It was the second fatal accident in Yellowstone this year. In February, a woman was killed in a snowmobile accident.