Nepal-based expedition guide Norbu Sherpa says the Nepalese government could take at least one action to prevent more deaths on the increasingly crowded Mount Everest: Stop issuing permits to those who are inexperienced.

Sherpa, who scaled the mountain nearly two weeks ago without incident, said the problem isn't so much the number of permits being issued, it's who they're being issued to.

And too many people are flocking to the popular destination without the proper fitness level or experience to make the ascent and descent, he said. (Many Sherpas use their ethnic group as their last name.)

"What I see, on average, is that people are coming with [a] very, very bad physical level," Sherpa told CBC News. "You really have to have a very good cardio stamina to go long distance."

'Death zone'

At least 11 people have been killed on the mountain in this 2019 climbing season — the highest death toll since 2015.

Because of the altitude, climbers have just hours to reach the top before they are at risk of pulmonary edema, when the lungs fill with excess liquid, making it difficult to breathe. But climbers have recently been experiencing large crowds bottlenecking the narrow passageway to the peak — known as the "death zone" — taxing limited oxygen supplies and causing fatal delays.

Climbers have described having to step over bodies in the snow to continue their trek.

"There is one rope, so you can imagine if somebody is getting really, really, really slow and the one behind has to wait," said Andrea Sherpa-Zimmermann, who is co-founder of Wild Yak Expeditions and married to Sherpa.

"If the person has no experience, has no clue about mountaineering, then it takes longer," she said. "So it's all about preparation and experience actually."

This year, a record number of permits, 381, were issued, according to the Nepalese government. They were accompanied by an equal number of guides from the ethnic Sherpa community.

This handout photo, taken on May 22 and released by Project Possible, shows the heavy traffic of mountain climbers lining up to stand at the summit of Mount Everest. (@nimsdai, Project Possible/AFP)

Sherpa-Zimmermann said while crowding at Everest is nothing new, it's getting much worse as the mountain continues to attract more and more people.

"There are more and more agencies which are selling Everest climbs as, not an easy climb, but something that everybody can do. And I think this is a major, major concern."

Nepal doesn't have any regulations to determine how many permits should be issued, so anyone with a doctor's note can obtain one for a $11,000 fee, Mohan Krishna Sapkota, secretary at the Ministry of Tourism and Civil Aviation, told the Associated Press.

Calls to cut back on permits

Some, like Calgary-based mountaineer Andrew Brash, who scaled Everest in 2008, said the Nepalese government needs to cut back on the number of permits issued.

"I don't know if I can see them doing this, but I really think they should really restrict the number of permits. Make it a lottery, whatever they have to do, but just change it. Because it's obviously out of control."

But before issuing a permit, Sherpa believes the government needs to check the experience of the climber.

"They have to really check their skills," said Sherpa, who has reached the Everest peak seven times.

Those with inexperience and without proper fitness or knowledge are generating problems for others, he said, jamming up the climb.

"[They are] coming without the proper fitness, without the proper knowledge, and he or she is [getting] stuck. Now [they are] making problems to other climbers. He or she is making the jam there."

In particular, Sherpa said, people come to Everest without having the experience of climbing other mountains with high elevations. Those experiences are important to inform one's body how it reacts to trekking at high altitudes.

"Some people, I ask them what is your background of coming to Everest. They've been only to Kilimanjaro and Kilimanjaro is just a walk," Sherpa said. "That's totally not enough to scale such area, such a risky mountain or huge mountain [as Everest]. That's the most dangerous thing."

Sherpa-Zimmermann said climbers need to know how their bodies react at different elevations — at 7,000 metres, then at 8,000 metres, because it's a "huge step" between the two. "And then Everest is nearly 9,000 metres."

Weather window

Co-ordinating expeditions to stagger the climbs at different times, so not everyone is making their ascent at the same time, would be difficult because of the short weather window, Sherpa-Zimmermann said. There's a limited number of days when weather conditions are at their best for climbing.

"The weather window is very, very short," she said. "Sometimes you're lucky, you can have two weather windows. But you need at least four days in a row of good weather.

"If you are physically perfectly in shape, you can maybe take the risk to go one day later or start a day earlier or something like this. But most of the people, they cannot do this."

Christopher Kulish, a Colorado climber, died on Monday during his descent from the summit of Mount Everest. (Christopher Kulish/Mark Kulish via AP)

But Brash, who made headlines in 2006 by giving up his own attempt to reach the mountain peak in order to save an Australian man, said there are often many good days of weather.

"There's not just a couple days, there's multiple opportunities, I think, almost every season," he said.

"[People] think, 'Well, this is going to be great weather window; we're there, we better get up there and do it.' Our whole thing — I remember this really clearly — was we're not going up in those days because there's just going to be too many people."