Nightfall on Tuesday brought to an end the search and rescue efforts for two climbers missing on treacherous Mount Hood for the past 11 days.

While rescuers try to remain upbeat about finding the hikers alive, there's a possibility searching could be limited Wednesday as a storm system is expected to bring freezing rain and snow to the area, news that bodes poorly for those hopes.

As efforts continue, officials in charge spent today wondering if the two could still be alive after examining photos the third, dead climber had taken of their trip up the mountain that show what the three had with them.

The photos found on Kelly James' body indicate the hikers — Dallas residents James Brian Hall, 47, and Jerry "Nikko" Cooke, 36, of New York City — were prepared but they were traveling light when they were likely thrown off their schedule due to an injury to James.

"Looking [at] what they had with them, I'm pretty concerned about how long somebody can last out there," Hood River County Sheriff Joe Wampler said of the hikers, who have been missing for 11 days. "I'm still looking for that stocking cap, that one glove, that candy bar wrapper that fell out of something."

But survival experts are telling Wampler to keep up the search and that, if properly trained, the climbers can still be alive.

And Wampler is listening.

"This office is not going to give up until somebody tells me the risk of doing this thing outweighs the result," Wampler said. "Until I hear that, I'm not going to give up."

Meanwhile, two fixed-wing aircraft scoured Mount Hood as part of a narrowed search for the climbers, who officials think could be either down a glacial crack or in a snow cave.

Avalanche search experts were being prepared to probe the snow with long poles in hopes that the missing climbers may be hunkered down in a snow cave. Other volunteers were searching lower elevations on foot.

"I've just got everybody on standby on both sides of the mountain right now," Wampler told reporters during what was supposed to be the final scheduled press conference Tuesday. "We'll search all day."

Search operations, however, have scaled down but narrowed in focus.

"The big search probably is over," Wampler said.

Teams are focusing on the trail the climbers agreed to take if something happened to them and on the areas around the snow caves in which they found some equipment and the frozen body of third climber, James, who was 48.

"I think they knew where they were at, but, nighttime, not ever being there before — there's some disorientation involved in this. But basically, I think, we need to concentrate … on where we know the cave was, where their equipment was found," Wampler said.

Clear blue skies, unlimited visibility and calm winds at Mount Hood were helping Tuesday's effort.

Wampler said Tuesday's aerial search will "give the opportunity for Brian and Nikko to stick their heads up out of their hole and rescue themselves," Wampler said. "We want to be there to see that, if that happens."

He added: "They still have a chance to save themselves if they can ... while the weather allows."

The search narrowed Tuesday to a small rugged section of ridge and glacier on the dangerous north side, but searchers say it has had up to 10 feet of snow since the two men, and another found dead, were reported missing.

Wampler said an injury to James probably threw the trio off their schedule.

"I think we're talking about three guys that had... the basic knowledge and equipment to get this done in the time periods that they had planned on, he said. "I think an injury threw that schedule all off and left them in a position of 'now what are we going to do' and desperation."

The body of James was removed by helicopter Monday from the 11,239-foot summit after rescue workers winched it up from a snow cave about 300 feet down the steep north side.

After examining the body, Wampler said Tuesday that it appeared James had a dislocated shoulder.

"Obviously, that had some affect on their climb, which forced them to make Kelly James comfortable where he was at and attempt to go get help," he said.

Wampler said the other climbers had likely left their injured companion in the cave to find help, but had to dig a shallow cave of their own on a steep slope as the bad weather worsened.

Wampler said the search for the two will continue for now as a rescue effort, not a recovery operation. But more bad weather is expected at midweek and Wampler said the chances for survival are less if the two were without shelter.

But Wampler said the dangers the rescuers are putting themselves into also needs to be considered, particularly on parts of the mountain when bad weather hits again.

"We are approaching that time where we need to make some serious considerations, whether we're spinning our wheels, because of the safety of the people going out there," he said. "We've talked to the family about that; they know."

Blizzard conditions severely curtailed early search efforts but weather improved during the weekend, when helicopter crews spotted a Y-shaped climbing harness anchored to the side of the mountain.

Search crews on Sunday found a snow cave and equipment but no climbers. They searched for a second cave and found the one containing James' body. James made a cell phone call from the cave on Dec. 10, telling his family the party was in trouble and the others had gone for help.

Wampler said Monday he is increasingly leaning toward the likelihood of a climbing accident.

The place below the second cave is called "the gullies," with a 60-degree slope and a treacherous 2,500-foot drop-off. About 13 climbers have died in the area in the past 40 years, Wampler said.

It appears the three got to the summit Dec. 8 after an exhausting and technically difficult climb and had planned to descend the gentler south side to Timberline Lodge that night.

Wampler said Monday they apparently missed the descent point known as the Pearly Gates and — cold, exhausted and facing high winds — decided to dig in and spend the night a few hundred feet over the steep north side.

They likely were clipped into the Y-shaped harness fastened to the mountain wall by an ice anchor, he said. It was spotted by Spec. Tim Handforth, flight engineer on the Pendleton-based Oregon National Guard Chinook helicopter, who said he was attracted to the straight line of the harness, a line out of place on the rugged mountainside. It set rescue crews on the spot, near to where James' phone call had been traced.

Rescuers said they found a soaked cell phone with James, whose identity was confirmed later Monday by jewelry, tattoos and scars.

Capt. Mike Ross of the Air Force Reserve's Portland-based 304th Search and Rescue Squadron said the effort topped any he knew of on Mount Hood.

He said survival odds drop with time "but some people beat the odds."

Frank James, brother of Kelly James, choked back tears Monday when he said a ring found on his brother's body inside the snow cave had confirmed his identity.

"This is a difficult day for all three families," James said. "I feel that I have two other brothers still on the mountain."

FOX News' Adam Housley and Liza Porteus and The Associated Press contributed to this report.