SAN RAMON (CBS SF) — Anxiety mounted Sunday for a San Ramon family as they waited any word about their 66-year-old father who has been lost in the Sierra since becoming separated from friends while hiking on July 8th.

Saeed Emadi was hiking near the Ice House Reservoir and Strawberry Point when he got separated from the group. His daughter, Zhila Emadi, told KPIX 5 her father was able to contact his friends via his cell phone. He told them he was on a hill, overlooking the reservoir. He said his cellphone battery was low and then the call ended.

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It was the last contact with Emadi. His friends called the El Dorado County Sheriff’s Office to report him missing a short time later.

Search teams aided by helicopters and drones have been combing through the area since July 9th. Footprints were found near Strawberry Point and identified as being made by the Costco-brand sneakers Saeed was wearing, Zhila Emadi said.

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The family said they remain hopeful because their father is an experienced hiker in the Tahoe area.

Another sign emerged when more footprints were found more than a mile away. Emadi’s family is optimistic, saying the presence of natural springs of clean water nearby could keep a hiker alive for an extended period.

“He’s very strong-willed and we definitely believe that he would keep fighting and he’s not going to quit,” Roya Emadi said.

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Saeed is described as being 6-foot-2, about 190 pounds with gray hair. He was last seen wearing a gray baseball cap, a white button-up shirt, light-colored striped shorts and blue sneakers.