Climbers abandon Everest

The journey to the summit of Mount Everest is a challenge that an increasing number have taken on since the summit was first reached in in 1953 by Sir Edmund Hillary and Tenzing Norgay. Until the late 1970s, only a handful of climbers per year reached the top of the world's tallest mountain, but by 2012 that number rose to more than 500.

Explorers are seen in 1922 at Camp II on the East Rongbuk Glacier. That same year, seven Sherpas were killed when they were caught in an avalanche during an expedition led by George Mallory.

George Mallory and Edward Felix Norton reach 27,000 feet on the northeast ridge of Everest in 1922. They failed to reach the summit.

Mallory returns to Everest In June 1924. He's seen here with his climbing partner Andrew Irvine at the base camp. This is the last photo of the the two before they disappeared on the mountain. Mallory's body was found 75 years later, showing signs of a fatal fall. The camera the pair were known to carry, and which may hold clues to their demise, has never been found.

Mountaineers are seen preparing to leave their camp during one of Eric Shipton's early expeditions on Everest in the 1930s. While Shipton never made it to the summit, his exploration of the mountain paved the way for others.

Shipton leads an expedition exploring the Khumbu Glacier icefall in November 1951.

Shipton is also known for discovering and photographing footprints of an unknown animal or person, like this one taken in 1951. Many attributed these to the Yeti, or Abominable Snowman.

Edmund Hillary sits at base camp in May 1953 before heading out on what would become the first successful ascent to the top of the world.

Hillary and Nepalese-Indian mountaineer Tenzing Norgay climb beyond a crevasse on Mount Everest in 1953. Upon meeting George Lowe, who had climbed up to meet the descending duo, Hillary reportedly exclaimed, "Well George, we knocked the bastard off!"

Members of a U.S. expedition team and Sherpas are shown with their climbing gear on Everest. The team, led by Jim Whittaker, reached the top on May 1, 1963, becoming the first Americans to do so.

Whittaker's team members climb Everest's West Ridge in 1963.

On April 5, 1970, six Sherpas died in an avalanche at the Khumbu Icefall. The icefall, at the head of the Khumbu Glacier, seen here in 2003, is one of the more treacherous areas of the ascent.

British Army soldiers and mountaineers John "Brummie" Stokes and Michael "Bronco" Lane above the icefall at the entrance to the West Col (or western pass) of Mount Everest during their successful ascent of the mountain. The joint British-Nepalese army expedition reached the summit on May 16, 1976.

In 1978, Reinhold Messner makes the first ascent without supplemental oxygen. Messner is seen here at Munich Airport showing reporters his frozen thumb after climbing to the top of Nanga Parbat in Pakistan, alone and without an oxygen mask.

French climber Jean-Marc Boivin becomes the first person to paraglide from Everest's summit in September 1998.

The 1996 climbing season was one of the deadliest, when 15 people died on Everest, eight in a single storm in May of that year.

Francys Distefano-Arsentiev became the first American woman to reach Everest's summit without bottled oxygen on May 23, 1998. However, she and her husband, Sergei Arsentiev, never made it off the mountain. They died after becoming separated while attempting to descend in the dark. At least one climbing party found Francys barely conscious, but there was nothing they could do to save her. Her husband's body was found years later. It is believed he fell while trying to save his wife.

Pemba Dorje Sherpa and Moni Mulepati became the first people to get married on Everest's summit, on March 30, 2005. The couple are seen here waving from base camp on June 2, 2005.

Mountaineer Ralf Dujmovits took this image of a long line of climbers heading up Everest in May 2012.

Jordan Romero became the youngest person to reach the summit, at age 13, on May 22, 2013. Jordan, right, is seen here on the summit with one of the Sherpas who helped him make the ascent.

Yuichiro Miura became the oldest person to summit Everest, on May 23, 2013, at the age of 80.

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• Though Mount Everest remains open, base camp exodus continues as climbers abandon the season


• Various reasons behind Sherpas' decision to abandon climb following deadly April 18 avalanche


• South Korean climber says Nepal government will extend his Everest permit, but fears he won't have another chance to return

Khumbu Valley, Nepal (CNN) -- Italian climber Claudio Tessarolo has been at Mount Everest base camp for the last 10 days, waiting to find out if his attempt to summit the world's highest peak can go ahead.

He says it's been 10 days of rumors -- 10 days of watching other expedition teams make the difficult decision to leave, one by one.

This morning, he and his team finally decided to pack up and follow them.

"For once, the local people decided about Everest," he says.

I've been climbing towards base camp through the Khumbu Valley for the last five days.

Helicopters have been a constant presence, breaking the beautiful silence that lovers of the mountains treasure.

They carry negotiators to Kathmandu, officials to base camp and climbers back home.

On the ground, I cross paths with yak caravans, ascending empty and descending with full loads.

"Why is everyone leaving?" a German climber asks me.

Time for change at the top of the world?

"There is still one month of opportunity before the monsoon arrives."

Sherpas battle over Mount Everest

Despite conflicting reports to the contrary, the mountain is still open.

The government has not issued any prohibition against climbing, releasing a statement on April 24 encouraging expedition teams to go ahead with the season.

But support for this season's climb has trickled away, day after day, since the April 18 avalanche that left 13 guides dead and three missing -- the deadliest accident in the history of the world's highest peak.

A group of about 50 people, mostly Nepali Sherpas, were hit by the avalanche at more than 20,000 feet just above base camp in the Khumbu Ice Fall.

Sherpas, an ethnic group from Nepal's Himalaya region famed for their climbing prowess, aren't officially stopping anyone from attempting the risky journey, though hundreds involved in the lucrative Everest trekking industry have refused to climb.

"Without the Sherpas we cannot climb and there is nothing we can do about it," says Tessarolo.

"We made Everest a circus. This year the Sherpas decided that the show will not go on."

Sherpas open the route on the Nepali side of Everest, through the treacherous Khumbu Icefall.

They fix the climbing lines all the way to the summit of Mount Everest, transport the equipment to make camp, climb next to their clients while carrying their oxygen and food, and rescue those in danger.

Without their assistance, making the long, dangerous journey is nearly impossible for all but the most experienced of climbers.

MORE: Everest avalanche: American climber recounts how Sherpa saved his life

Mixed feelings on canceled season

"We made Everest a circus. This year the Sherpa decided that the show will not go on."

Climber Claudio Tessarolo

It wasn't a unanimous decision by Nepal's Sherpa to abandon the season -- there's no unanimous motive.

Some don't want to climb because they're in mourning -- a sign of respect for their friends who died in the avalanche and their families.

Others don't want to climb for religious reasons.

The Sherpa spiritual code of conduct, which interconnects humans and nature, has been violated, they say.

To put it simply, the gods are angry.

Some refuse to climb for political reasons: they want better insurance from the Nepal government and scholarships for their children.

Some don't want to climb because of safety: there have been several avalanches reported since the tragedy.

There have even been reports of threats of violence to climbers who try to continue.

It's still possible, according to some reports, to find guides willing to take you to the summit on the northern, Chinese side of the mountain.

But in Nepal the season is looking bleak.

MORE: Discovery calls off coverage of Everest wingsuit jump

'How will I convince my wife to let me go away again?'

The Nepal government makes about $3 million from royalties on Everest each spring season.

More than 330 foreign climbers had been given permission to climb Everest over the next couple of months, with an estimated 400 guides helping them, spending between $40,000 and $90,000 each in their attempt to scale the mountain.

The short window, May 15-30, is usually the best time to make an attempt to reach Everest's peak.

As discussions took place on the fate of the Everest season last week, many climbers left base camp to continue their acclimatization process on other mountains in the region.

"When we went back, we found base camp empty," says Bae Young Rok, a South Korean member of the Kyungil University Alpine Club.

Everest expeditions in doubt

"There is nothing we can do but leave as well."

He says the Nepalese government told him his Everest climbing permit will remain valid for the next five years.

"That's fine, but how will I convince my wife to let me go away again for two months?"

One of the reasons an Everest expedition takes so long is the time required for multiple rotations up and down the mountain to help the body adjust to the thin air, says professional climber Alan Arnette, who summited Everest in 2011, on his blog.

"A typical Everest climber will spend 10-15 days sleeping high on the mountain above Base Camp before going on their summit attempt," he says.

"They sleep at ever-increasing altitudes to trick the body into making the necessary physiological changes, especially with respect to respiration, the key to survival at extreme altitudes."

Sherpas seek better employment opportunities

On the route to base camp I meet Tsering Sherpa, who is making his way down from base camp.

"I am ready to climb," he says.

"I want to stand by my clients; it is their decision whether to climb or not."

He says the leader of his team called the expedition off on Monday.

"He told us that the icefall is too risky."

Some teams left earlier out of respect for their Sherpa, many of whom work on climbing expeditions only because they don't have access to better economic opportunities.

They make up to $6,000 per season and usually get a summit bonus if their clients reach the top of the 8,848-meter (29,020-feet) mountain.

It's a stark contrast to what drives the foreign visitors to climb.

"In our time the best job available was climbing; it's not anymore," says Natang Sherpa, who owns the Moonlight Lodge in Namche Baazar, a popular acclimatization village among tourists.

Her daughter is now a medical doctor living in the United States.

"Tourists asked me how long have I been a Sherpa. I am a Sherpa since I was born! Some of us become porters and climbers, most of us, luckily, can avoid it [nowadays]."

Other Nepalese ethnic groups are starting to replace the Sherpa, as they manage to secure better jobs.

Among the 16 people dead or missing in the April 18 tragedy, three are from other ethnic groups.

MORE: Mount Everest climbing season up in air after avalanche deaths

Only a handful remain

For the few still hanging on in base camp in the hope of making the summit, their chances get slimmer with each day that passes.

The Khumbu Icefall moves one meter per day: the ladders are lost, the lines broken.

None of the camps on the mountain itself are operative, I'm told, and nobody has reached Camp 3 yet -- one of four camps set up on Everest en route to the summit.

Nobody is left to do the heavy work for the foreign climbers, and most have come to the realization over the last few days that climbing is not a possibility for them.

Until the late 1970s, only a handful of climbers reached the top each year.

The number topped 100 for the first time in 1993.

By 2004, it was more than 300. In 2012, the number was more than 500.

The deadliest year on Everest was 1996, when 15 people died. Another 12 climbers were killed in 2006.

MORE: Everest climbers, widower recount deadly traffic jam on top of the world

Journalist Manesh Shrestha contributed to this report.