According to Plumas News,

Plumas County Search and Rescue is in its fourth day of searching for Frank Christopher, 53, of Chico who went missing near the Rock Creek drainage in the Feather River Canyon. Christopher’s family reported him missing Sunday when he failed to return from a camping trip. His truck was found parked near the area that is now being searched. Many other resources have aided Plumas County Search and Rescue, including four Air National Guard personnel using a UH-60 Black Hawk helicopter, eight search and rescue units from El Dorado County, three units from Butte County, two Office of Emergency Services (OES) personnel, and five Plumas County Sheriff’s deputies.

According to the Plumas team, the search area has expanded significantly, and multiple agencies have contributed some of the best search equipment available, including FLIR thermal imaging. The Rock Creek drainage is extremely steep and dangerous. The Air National Guard was unable to land personnel near the search area, but a specialized mountain team penetrated deeper into the drainage on foot and located some tracks on a ridge line that may have been the subject’s. Air National Guard flew the entire river search area multiple times yesterday.