Dreams shattered and counting their losses, many foreign climbers say they might never return to Nepal to climb Everest, upset by ugly scenes at base camp and what they see as the government's mismanagement of the peak.

Climbing Everest from the Nepalese side -- the easiest and most popular route up the world's highest peak -- has been effectively closed this season after the worst ever accident on April 18.

Sixteen Nepalese sherpa guides died in an avalanche, sparking a labour dispute between them and the government and a boycott that left foreign expeditions no choice but to abandon their plans.

US climber Robert Kay had planned a third attempt at scaling the peak this year, after being forced to turn back twice due to bad weather in 2010 and 2013.

The 52-year-old hired two personal trainers, spent upwards of $40,000 and took ten weeks off from his job running a motorcycle dealership in Nebraska all for an opportunity to reach the summit of the 8,848-metre (29,029-foot) mountain.

"I think about that mountain 10 times a day every day," Kay told AFP in Kathmandu, where others are arriving on their way home.

The father of three, including two daughters adopted from Nepal, described the days since the April 18 avalanche as a "rollercoaster of emotions".

"One minute, it was 'no climbing will happen'. The next minute, 'the government is going to make a deal with the sherpas and we are going to climb'. Then the next day, 'it's off again'. It was exhausting," Kay explained.

For some, like British teenager Alex Staniforth, who was diagnosed with epilepsy at the age of nine, the heartbreak has prompted a rethink of his future plans.

"This is something I never saw coming. I don't know... whether I could create the same momentum, put the bad memories behind me to motivate and dedicate myself to another attempt," Staniforth wrote on his blog.

"The seeming wastage of sacrifices, suffering and sheer dedication required -- the countless hours of hard training, 15 months of persistence with fundraising, doubts and overcoming setbacks -- make this extremely painful," he blogged.

- 'Damaged Nepal's image' -

Seasoned climbers returning from Everest base camp described a tense atmosphere, saying it revived memories of last year's infamous brawl between three Europeans and a group of sherpas that shocked the mountaineering community.

The disaster has highlighted the huge risks borne by guides on behalf of foreign clients and fuelled demands for better death and injury benefits after the government initially offered $400 to families of the bereaved.

Negotiations between guides and the government for improved conditions are underway.

US climber Kay said all the sherpas on his team wanted to climb, but were afraid to proceed due to threats from other guides.

"They were told by this younger, angrier lot that 'if you go ahead, we know where you live'," he said.

Other mountaineers said that the response of some climbing companies to the disaster may have contributed to the problem.

"We had a memorial ceremony for the lost sherpas, where I felt that some Western mountaineers were very insensitive, trying to rally people to climb and get back to work," Australian climber Gavin Turner said.

"They were behaving like we were trying to win a football game. It just highlighted the gulf between Westerners and sherpas. The mood changed," Turner, 38, told AFP in Kathmandu.

The former head of the Nepal Tourism Board, Prachanda Man Shrestha, said that the closure would have implications for the tourism industry, one of the country's top earners of foreign currency.

Nepal earns more than $3 million from Everest climbing fees annually and the country attracted some 800,000 tourists in 2012. Annual revenues from tourism amount to $356 million, nearly two percent of Nepal's GDP.

"The Everest economy per se is not that important -- the bigger problem is what this means for Nepal tourism as a whole. This has damaged Nepal's image in the eyes of climbers and non-climbers alike," Shrestha told AFP.

Although officials have promised foreigners that their climbing permits, usually at least $11,000 a piece, will be extended for five years, many frustrated mountaineers say they will try to scale Everest from China instead.

"I want to climb next year but I am considering the Chinese side. I have lost confidence in the Nepalese government's ability to manage the mountain," said Turner.