(CNN) Too weak to stand or walk, William M. LaFever sat in a shallow river bed in the south Utah desert, awaiting rescue that came more than a month after his family last heard from him.

Thursday afternoon, a helicopter flying in the Escalante River gorge spied the bearded LaFever, 28, who had lost 50 pounds and eaten frogs and roots in his desperate effort to stay alive during his walk from a Utah city to Page, Arizona.

“We came around the corner and we were pretty amazed to see him alive and sitting up,” Shane Oldfield, a Utah Highway Patrol helicopter pilot assisting the Garfield County Sheriff’s Office, told CNN Friday.

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