PHOENIX — The parents of a 30 year-old Arizona State University graduate student are holding out hope their son is still alive.

David Yaghmourian vanished while hiking on Oregon's Mount Hood Monday.

The Valley man’s parents say he left for Oregon Thursday to see his high school friend out there and hike around the base of Mount Hood. They camped out there Friday, Saturday and Sunday. On Monday, his friend says they headed back but were both tired and sore. Yaghmourian's friend, Hayden Kirschbaum, says he left Yaghmourian and they planned to meet up again at the lodge.

“I was feeling sick earlier that morning so I didn't want to spend too much time out there. We were so close about a half hour from the lodge, with clear visibility so we talked and he said, 'Yeah I'll take some extra breaks— sounds good. I'll meet you at the lodge,” Kirschbaum said.

Fog moved in Monday, bad weather hampered visibility Tuesday, but Wednesday, the skies cleared.

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“I'm feeling very optimistic the person we are looking for is in a tent, in a sleeping bag, and in good shape,” said Erik Broms, Rescue leader for Portland Mountain Rescue.

Yaghmourian's parents say he’s an avid hiker. He had several supplies, like a tent, a water filtration device and even a sleeping bag that withstands weather as cold as 30 degrees.

The ASU student graduated from Mountain Ridge High school. His parents say he’s also a research analyst assistant at ASU’s Mary Lou Fulton Teachers College, and he is constantly hiking Valley mountains.

“He’s very bright, very analytical, and so we’re thinking that he will figure out a way to get out of whatever situation he’s in,” said Yaghmourian's mom, Mary Ellen.