"We've done everything we can at this point," said Sheriff Joe Wampler, choking back tears after returning from one last, fruitless flyover of the 11,239-foot peak.
Wampler said the men's families made the decision to end the search as yet another snowstorm barreled in.
"It was pretty much their conclusion. The chance of survival is pretty nil. I don't think I can justify putting any more people in the field with the hope of finding them alive," the sheriff said.
He said the operation is now a "recovery effort."
Three climbers in all were reported missing in the snow on Mount Hood on Dec. 11. One of them, 48-year-old Dallas landscape architect Kelly James, was found dead in a snow cave on Monday. Volunteers continued scouring the mountains for signs of James' climbing partners, Brian Hall, 37, and Jerry "Nikko" Cooke, 36.
Film developed from a disposable camera found in James' pocket show the three men had enough gear and food for a quick climb to the top of the mountain, but not for a longer period of time, while exposed to the elements, reports .
Ice axes left in a crude shelter indicate the men had a difficult stay and moved forward without crucial tools.
Exclusive: Katie Couric will interview Karen James, widow of Mount Hood climber Kelly James, on Thursday's CBS Evening News at 6:30 p.m. ET/PT, and on Friday's The Early Show.
The snow cave, cut into the ice of a nearly vertical cliff, is the last sign of the two men, who are thought to have left the injured James to seek help. It is possible Hall and Cooke were swept off the mountain by 100 mph winds, were buried in last week's blizzards or created a shelter for themselves by burrowing into the snow and sharing their body heat, as climbers are trained to do.
Search teams made a full-scale attack of the mountain over the weekend. But the search was scaled back to two air teams Tuesday and the rest of the crews were put on standby.
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Wampler announced the end of the search after personally piloting a Piper Cub over the mountain for new clues and finding none — no tracks, no signs of snow caves, no other debris.
"Right now things are moving in from the west," he said of the snowstorm. "That window has shut on us."
Even before the sheriff spoke, all of the volunteers had returned to regular lives and helicopters used in the search had returned to their bases.
"I feel good abut what I did. I wanted to do what I could for the family," Wampler said. "You start something you want to finish it."