KATHMANDU (Bloomberg) - Ms Ada Tsang remembers the ground shaking and then trying to zip up a tent flap before the roaring ocean of snow overtook her. Ice and rocks flew into her face and Ms Tsang, a high-school teacher from Hong Kong, was slammed to the ground, unconscious.

"Everyone just yelled, 'Run! Run!,'" she recalled as she recovered in a Kathmandu hospital, her face cut and swollen and her head bandaged all around. "Eventually it caught up and hit everyone."

When she awoke, Ms Tsang saw bodies strewn around Mount Everest, just some of the victims claimed by the earthquake that rocked Nepal on Saturday. The official death toll now numbers more than 3,700 people, including 19 on the mountain. Those figures will almost certainly increase.

For the second-consecutive year, fatal natural disasters struck Mount Everest, hitting one of the most important revenue sources in Asia's second-poorest country. IHS, a consulting firm, says rebuilding costs could "easily exceed" US$5 billion (S$6.65 billion).

That's about one-fifth of the annual output of the mostly agrarian economy, which depends on tourism and remittances for foreign exchange.

Since New Zealander Edmund Hillary and Nepali Tenzing Norgay reached the summit in 1953, more than 4,000 people have followed, creating a sizable industry. Websites for American expedition companies advertise group trips to the top with western and Nepali guides exceeding US$50,000 per person and more than twice that for ascents with a personal western guide.

For a sherpa, the job provides a salary of up to 700,000 Nepalese rupees, said Mr Bhim Paudel, operations manager for a trekking company in Kathmandu. That's about US$6,900 in a nation where the World Bank pegs per capita income at US$750.

Mr Paudel said that he knows there are bodies of guides waiting to be collected at the base camp. He hasn't had time, though, to think about compensation for their families.

"Our first priority is the injured people," he said. "The dead people are already dead. There's nothing you can do for them."

It's dangerous work.

"People go to Everest knowing that there are risks, objective dangers which they don't have control of - such as traveling through the Khumbu Icefall from base camp to camp one, the risk associated with mountaineering at very high altitude," said Mr Tom Briggs, marketing director for Jagged Globe, a British-based company that leads groups to Everest.

"But they don't go to Everest thinking they might be caught in an earthquake."

Estimates vary for how many people were on Everest when the shaking earth triggered the avalanche.

Mr Paudel said there were about 1,000 at the time, of whom 400 were climbers and the rest porters and sherpas, the ethnic Nepali group famed for leading hikers up the tallest mountain in the world.

Ang Tshering Sherpa, president of Nepal Mountaineering Association, a group that promotes tourism, put the total at 800. He said he doesn't expect "there will be more bodies discovered" on Everest.

It may be many days before there's opportunity to comb the mountain and see if he's right.

A group of light helicopters was able to dart up to a higher-altitude camp on Monday and ferry most of the 180 hikers who'd gotten stuck on the mountainside down to Everest's base camp, said to still be inhabited by hundreds of people. An icy stretch between the camps known as the Khumbu Icefall had been rendered impassable.

While Ms Tsang recalls five people in her group perished, she says she saw 30 to 40 bodies on the mountain.

The earthquake was described in a blog post by a guide working for US-based Rainier Mountaineering Inc., who was at a camp at another mountain in Nepal, as feeling "as if we were inside a snowglobe being shaken by God".

Mr Paudel, sitting in the dimly lit offices of Himalayan Guides Nepal as six men planned rescue operations, recalled the 2014 climbing season, which was cancelled in Nepal after 16 guides died in an avalanche. He's had enough of the mountain for now.

"Hopefully, people will stop coming this season," he said.

The state newswire in China - Everest straddles the Nepal-China border - reported on Monday that the country called off all spring climbs on its side of the mountain.

Mr Briggs, of Jagged Globe, said that he "can't imagine" that tours will continue this season.

"It's difficult to think ahead to potential, future Everest expeditions," he said.

A Google executive named Dan Fredinburg, who traveled to Everest with Jagged Globe, was among the dead.

Mr Carsten Lillelund Pedersen, a travel blogger and climber, said in an interview with Bloomberg Television that Nepal is now faced with a crucial decision: "Nepal needs to figure out if they want all the tourists to flee Nepal or want them to stay. Because Nepal needs money to rebuild their country."

"If we can't climb Everest this year because of the earthquake and avalanche - and it is a tragic story - then I don't think many will come back next year," said Mr Pedersen, who recounted hiding behind a stone setting as the avalanche engulfed him.

As she recalled the noise and the pain of her world turning upside down, Ms Tsang sat near a makeshift ward of mattresses on the ground under a tarp roof at the Swacon International Hospital in the capital. Some patients refused to go inside to get treatment for fear of another earthquake.

As for Mount Everest, she said: "No one's going back up after what's happened."