Back home, concern began to grow when they failed to return to the United States as scheduled.
"On Dec. 21 she said she'd be home," Arlene Burns, a friend of the couple who is coordinating search efforts, told The Early Show co-anchor Hannah Storm.
Burns said she believes that foul play could be at the root of their disappearance, but there is no substantial evidence pointing in any direction. The main goal is to continue searching, she said.
"It is, indeed, like finding a needle in a haystack. Charlie and Chris left clues in the e-mails they last sent to friends … it's like a treasure hunt," Burns said. "With this team on the ground — which is all of Charlie's and Chris' great friends — have rallied with tremendous amount of collective intelligence. We have been able to understand what they most likely did do and where they might be."
Complicating the situation, Burns said, is the rough terrain. The couple was climbing in what she called one of the most remote and wild places on Earth.
"Here in the United States, for example around Mt. Hood, where you can call up and get a helicopter, this is all border area, there isn't civilian aviation. It's days driving between these villages," Burns said.
The good news is that Boskoff and Fowler are extremely experienced. Boskoff is one of the top female altitude climbers in the world and Fowler is also a top rated mountaineer.
"We are hoping for that Christmas miracle," Burns said.