By Andreas Preuss CNN

(CNN) -- Police in a California county have a warning for camera-toting thrill seekers: "You can lose your life and none of that is worth a selfie!"

The message was posted on the Placer County Sheriff's Office Facebook page after a woman fell 60 feet off the Foresthill Bridge on Tuesday. The 730-foot-tall bridge is the highest in California and one of the highest in the United States.

The Sheriff's Office said the unidentified woman from Sacramento and a group of friends were walking on the bridge's girders when she "attempted to take a selfie and fell. Landing on a trail below."

The woman had to be airlifted to a nearby hospital. Paul Goncharuk, a friend, told CNN affiliate KOVR that "she was knocked unconscious, suffered a deep gash to her arm and fractured bones that will require surgery."

Goncharuk, who told KOVR that he was there, also confirmed the police information, telling the affiliate that "they were taking a picture on the bridge, and then the big bolts that are holding the beams together, she stepped on them kind of weirdly and lost balance and fell backwards."

The bridge's off-limits underbelly seems to be a popular, but dangerous spot for social media posting.

Police have started patrolling the area after a series of pictures and videos of people dangling from walkways under the bridge.

"It's a cool place to take pictures, but obviously not worth the risk," Goncharuk told KOVR.

Trespassers found on any closed portion of the bridge will be arrested, police said.

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