(CNN) -- A Pakistani rescue helicopter on Wednesday will try to evacuate an Italian climber who survived a deadly ice avalanche four days ago on K2, the world's second highest mountain.
The site of the accident on K2 is what climbers call the "Dead Zone."
The chopper was unable to attempt the high-altitude operation Tuesday because of "extremely poor weather," Askari Aviation said on its Web site.
The survivor, Marco Confortola, arrived Tuesday at K2's base camp, where he is being treated by doctors for frostbite on his feet, according to updates of the rescue operation provided by his expedition team's Web site.
Two other survivors, both Dutch men, were flown to a hospital in Skardu, Pakistan, on Monday, a day after making their way down the mountain to base camp. They are also suffering from frostbite.
Once the weather conditions clear, a helicopter will take Confortola to the same hospital, according to Pakistani Ministry of Tourism Secretary Shahzad Qaiser.
The three men were part of a group "stuck up high on the mountain" after an ice avalanche in the early hours of Saturday, team spokesman Michel Schuurman said. Watch how the climbers were rescued »
The tragedy -- which struck as the group was on the way down after 17 climbers had reached the summit -- left 11 people dead, including a sherpa who had gone up to assist in rescue efforts, according to mountaineers working with the climbers involved.
One of the Dutch survivors, Norit expedition leader Wilco Van Rooijen, was missing after the avalanche and there were concerns that he had not survived. But a blog entry posted on Saturday read "Wilco found alive!" and said his survival "is bound to go down as one of the greatest mountaineering tales in K2's history."
The avalanche struck down the safety ropes that the climbers planned to use to descend the mountain, Schuurman said.
"They had to descend without any safety lines and in that descent we know that some climbers have slipped down and their whereabouts are unknown," he said.
K2, which is near the Pakistan-China border, is considered by many climbers to be more technically challenging than world's tallest peak, Mount Everest.
The site of the accident, about 8 kilometers (5 miles) up the mountain, is what climbers call the "Dead Zone," because the body would never recover if stuck in such freezing conditions with so little oxygen, said Pat Falvey, a climber in Ireland who is in touch with the climbers and posting updates online for one of the climbing expeditions.
While the climbers and rescuers who made it down safely were not immediately in any condition to speak publicly, they told Strang and Falvey what had happened.
On Friday, the 17 climbers reached the summit together -- one of the largest groups ever to reach the summit simultaneously -- said Falvey.
The climbers were Dutch, Irish, Italian, French, Norwegian, Korean, and Nepalese citizens.
As they were descending, a "moving river of ice broke loose ... like an iceberg breaking loose from a glacier," and it knocked down the fixed rope that the group had been using to move safely from the higher reaches to a camp at a lower altitude, he said.
The rope's collapse knocked down three climbers, sweeping them away in an avalanche of ice and killing them, he said. Map of the area »
"Not only did it wipe away the fixed ropes, but it brought the whole slope into icy, dangerous conditions."
Two climbers managed to make it to base camp, but many of those stranded decided the best course of action was to wait and hope rescuers could put up ropes and make it up, Falvey said.
As time went on and rescuers didn't come, the remaining climbers decided their only chance at survival was to go into the treacherous, icy conditions of the mountain's bottleneck and try to make it through. But as they did, some climbers fell to their deaths.
A few managed to survive, with the help of rescuers, Falvey and Strang told CNN.
It is the deadliest incident on K2 since 1986, when 13 of 27 climbers died after summiting the peak, according to Outside Magazine.
Strang said the tragedy could have been avoided. Too many people were climbing together "at a very slow speed," and should have turned around to begin their descent sooner, he said.
"Coming down at dawn, in the dark, with little oxygen is very, very dangerous," he said.