A traveling nurse practitioner who went missing on a hiking trail in Northern California over a week ago has prompted a massive search effort.

Ann Herford, a 66-year-old Michigan resident, was reported missing Wednesday on the Arnold Rim Trail in Arnold after she never showed up for work at Adventist Health in Sonora, the Calaveras County Sheriff’s Office said. 

Herford was staying alone at the Best Western in Sonora and was last heard from on Nov. 11, when she had "expressed interest in hiking" during a breakfast with a friend, according to authorities.

"She wanted to take advantage of hiking and going to see the mountains up here," Ann Wettengel, who met Herford a few weeks prior to her disappearance, told KCRA-TV.

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Ann Herford

Ann Herford, 66, is a traveling nurse practioner from Michigan. She was working in Sonora, California, at the time she went missing. (Calaveras County Sheriffs Office)

A resident reported seeing Herford near a trailhead where her car was found on Wednesday. 

Arnold Rim search area

An aerial view of the search area near Arnold Rim Trail, where Ann Herford was believed to have gone hiking before she went missing. (Calaveras County Sheriff's Office)

Family members told authorities that she enjoyed hiking, though she lacked the necessary skills to survive in the wilderness and would never plan to travel more than a couple of miles at a time.

search team on Arnold Rim

More than 120 searchers and five canine teams have joined the effort to locate Ann Herford. (Calaveras County Sheriff's Office)

On Saturday, the effort involved 120 searchers, five canine teams, aircraft and people canvassing the Arnold area when adverse weather conditions temporarily paused the search.

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When the search resumed Sunday, the sheriff’s office sent additional teams into the field, which included ground crews, a helicopter and drones, canine teams and specialized high angle rope crews.

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Authorities asked anyone with information about Herford’s whereabouts to contact the Calaveras County Sheriff’s Office at 209-754-6500.