About 200 climbers are expected to attempt to scale the 29,035ft mountain between Friday and Sunday, Nepali mountaineering official Gyanendra Shrestha said. Some have been at a staging camp for days, waiting for a window of good weather.
Some 208 climbers headed to the summit last week, with four dying on Saturday in one of the deadliest days ever on the mountain.
Ha Wenyi of China, Eberhard Schaaf of Germany, Nepal-born Canadian Shriya Shah and South Korean Song Won-bin died on their descents from the summit, apparently from exhaustion and altitude sickness.
Mr Shrestha said a Nepalese Sherpa guide who had been reported missing reached the base camp safely on Monday after becoming separated from his group.
The deaths have raised concerns about overcrowding above the highest camp on the mountain. The area towards the summit is nicknamed the “death zone” because of the treacherous conditions and low oxygen level.
Describing a “traffic jam” of climbers on Saturday, Mr Shrestha yesterday said climbers were heading to the summit at 2:30pm, even though 11am is the latest start time recommended. That meant climbers were staying too long at high altitudes and exhausting their oxygen supplies because they didn’t anticipate having to wait.
Nepalese authorities acknowledged the safety concerns but said they can’t turn any of the climbers away.
Nepal’s tourism ministry spokesman, Bal Krishna Ghimire, said: “The climbers have received the permits to climb within specific dates. We cannot say who gets to get to the summit on which dates because of the unpredictable weather. When weather clears up they all want to benefit.”
Apa, a Nepalese Sherpa guide who has scaled Everest a record 21 times, said climbers are eager to take advantage of good conditions because they are afraid they may not get another chance to climb to the summit.
He said the traffic jam of climbers going up and down the same icy trail makes it hazardous, especially with climbers already being exhausted from having climbed all night from the last camp, at 26,246ft.
“And having to wait for extra hours and the delays only makes the situation worse,” said Apa.
Mr Ghimire said it is up to the climbers and their teams to assess the conditions and safety, adding: “We have officials at the base camp, but beyond that it is mostly up to the climbers.”
He said that eventually, the government plans to set up a seasonal office at the base camp equipped with doctors, weather experts and security personnel. They also have plans to give each climber a tracking device.
More than 3,000 people have climbed Everest since Edmund Hillary and Tenzing Norgay became the first to do so in 1953. Some 225 climbers have died attempting it.
The deadliest day was 10 May, 1996, when eight people were killed. The main reason was said to be that climbers who started their ascent late in the day were caught in a snowstorm in the afternoon and lost their way.
The climbing season normally runs from late March to the first week in June, but this year the season’s first clear conditions were on Friday and Saturday. A windstorm hit the higher altitudes by Saturday afternoon.