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Apr 232021
Everest Oxygen

Up to a foot of heavy snow at Everest Base Camp brought climbing to a halt the last 36 hours. Teams will let the snow settle for a day or so before heading higher for acclimatization starting this weekend. Record permits, now approaching 400 will guarantee crowding unless the weather is significantly better than usual. But with more people not using O’s, are they at greater risk?

Big Picture

The season remains on track even with the snow delays. By now, most teams would have spent at least one night in the Cwm, but they will get there next week, spending a couple of nights at C1 and a few more at C2, then back to EBC. The first week of May, they will return to tag or sleep at C3, then back down to wait for the weather window. Most likely, the ropes will reach the summit next week taken by a Sherpa team. I suspect the first 2021 summits will center around April 30, 2021.

EverestER, the volunteer hospital at EBC, gave this excellent update on Friday:

So far, our team of volunteer doctors have seen 127 patients, which is just about average from past years. Diagnoses of high altitude cough, musculoskeletal aches and injuries, sore throats, gastritis are all right on target with what we expect to see year after year. The video we posted a few days ago was of Lakpa rescuing our first patient with major trauma (recovering in a hospital in Kathmandu after surgery; Dr Kharel jumped in the Heli to accompany the patient en route.) But what ISN’T the norm is … well, where do we begin.


Puja ceremonies, usually a festive social gathering with mixing of camps, eating and meeting with friends is now a private event. Some expeditions have forbid their members to visit other camps to try to keep everyone in a safe bubble. Masks are worn between camps (remember that breathing at 5350m is a chore even without a mask!) Camps are roped off and signed to discourage uninvited guest visits. Some close contacts are isolating in their tents as we’ve had a few confirmed cases of covid with evacuation from EBC. Despite the challenges, climbing continues as teams move farther up the mountain to establish high camps and acclimatize their bodies for their summit bids when the weather window opens.

Of note, a Norweigan climber, Erlend Ness, was evacuated from EBC to Kathmandu where he has undergone a dizzying series of tests, diagnoses, and misinformation. He was told he had HACE, then AMS then tested negative for COVD, then positive and positive again. He is in a second hospital recovering but is worried about how he will pay for the treatment. The insurance he thought he had for COVID medical expenses only covered the evacuation.

Also, a female Indian climber was evacuated from EBC with COVID plus a trekker returned to Kathmandu with the virus. Needless to say, COVID is in the Khumbu and spreading. Government officials are either pointing fingers at poor communication from hospitals or saying there is no problem. Meanwhile, Nepal continues to see a spike in overall cases throughout the country.

Internet Issues

Multiple teams are squeezing through short messages saying that the Internet was down due to the heavy snow and high winds. But as of early Saturday morning Nepal time, it appears to be working again.

Oxygen on Everest

With only a few people climbing this spring without supplemental O’s let’s take a deep dive into supplemental oxygen.

Climbing Everest with supplemental oxygen has become standard for 97% of all climbers, starting with Mallory and Irvine in 1924. As with all mountaineering technologies, oxygen systems have seen many changes that have enabled a generation of summits that might not usually occur.

Climbers use supplemental oxygen to give them an edge while pushing to the summit of a mountain like Everest at 8848 meters. At that altitude, the available oxygen is 33% of that at sea level. It is like running up a staircase while holding your breath two out of every three steps. To summit Everest without using any supplemental oxygen anytime on the climb is rare. The Himalayan Database shows that 216 out of the 10,185 summits used this pure manner.

Providing supplemental oxygen at 8000 meters in high winds and extreme temperatures are not simple. Valves freeze, masks deform in the wind, ice forms in tubes, and many more problems prevent the delivery of the right amount of oxygen at the right time. Too much and there is a waste of precious gas, too little and a climber might die.

The basic principle used by all systems is to transfer oxygen held in a metal cylinder usually carried in a backpack through a rubber tube to a mask covering the climber’s mouth and nose. An adjustable regulator attached to the top of the cylinder controls the oxygen flow to some a reservoir where it is delivered as the climber inhales. A complicated valve prevents a climber’s exhaling into the reservoir.

The Early Designs

In the early 1900s, it was unknown if a human could live at extreme altitudes, including climbing Everest. They made serious efforts to design “breathing” systems, but they were heavy, bulky, and sometimes didn’t work. The original oxygen systems designed for climbing began with a device created by George Finch in 1922. Finch and his teammate Geoffrey Bruce reached an altitude on Everest of 27,250 ft (8175 m), setting a record using their open circuit system that weighed 33 pounds (15kg).

One of the great debates on whether Mallory and Irvine summited in 1924 was around their oxygen system. Irvine was brought onto the expedition for, amongst other reasons, his expertise on these systems, and modifications were made until they left for the summit.

Oxygen on Everest’s First Summit

In the 1950s, when the Swiss and British restarted attempts on Everest, the technology had advanced based on two World Wars. In 1953, almost thirty years after the first attempts, Sir Edmund Hillary and Tenzing Norgay reached the summit with a much improved and lighter (22 lb/10 kg) system.

The Hornbein Mask

In the 1960s, Navy doctor and mountaineer Tom Hornbein made more progress with updated masks used by Navy pilots to be more efficient and easier to use. The appliance company, Maytag, produced a limited number of these masks for use in the 1963 America climb.

One of the significant improvements was that the Hornbein mask had only one valve that prevented breathing back into the rubber bladder from which oxygen flowed from the tank. When the climber breathed, he took oxygen from the bladder, not directly from the tank. This system made breathing easier and provided a steady supply of oxygen. The basics of the Hornbein mask design are still the basis for all masks used in mountaineering today.


Alan with Poisk oxygen mask on Everest in 2002

Alan with Poisk oxygen mask on Everest in 2002

The Russian company, Poisk, commercialized oxygen systems for climbers starting with an Everest expedition in 1982. Their mask used the Hornbein design.

They manufactured small lightweight (7.7 lbs/3.5kg) gas cylinders made from titanium alloys covered in kevlar fibers holding another sealed container made of carbon fiber, fiberglass, or organic fibers. In addition, they provided regulators with adjustments in 1/4 liter per minute lpm) increments up to 4 lpm. A climber could go for 6 hours with this system at 2 lpm.

But this system was not perfect as I experienced on my first climb on Everest in 2002. In hindsight, I believe I climbed to the Balcony (27,200’/8250m) without supplemental oxygen due to the excessive leaking of the mask and perhaps some design issues.

The valve in the original mask design often allowed a climber’s exhale to enter the rubber reservoir preventing new oxygen from refilling the reservoir, thus sending oxygen directly to the mask where it leaked out or was unused as the climber exhaled. This flow was often due to the valve freezing from the moisture in a climber’s breath. Poisk introduced a new line of masks to address these issues.

Some commercial operators took oxygen systems into their own hands. International Mountain Guides (IMG) began designing and contracting their proprietary cylinders in 1991, choosing a larger tank that would supply climbers with 10 hours of oxygen at 3 lpm. I used this design for my 2011 Everest summit.


The Poisk system was the only game in town until the early 2000s when Ted Atkins introduced his TopOut mask. His approach was based on frustration with the Poisk mask. Atkins said the Poisk masks leaked, provided oxygen at a steady flow regardless of the climber’s needs, was uncomfortable, and often froze in the harsh extreme of 8000-meter expeditions. Also, the Poisk mask continued to bring oxygen into the mask as the climber exhaled, thus increasing the waste.

Alan with Top Out oxygen mask on Everest in 2011

Alan with Top Out oxygen mask on Everest in 2011

The TopOut mask aimed to solve those issues using the equivalent of a plastic pop bottle as a reservoir. This approach allowed for a variable flow of oxygen as the climber’s efforts ranging from rest to extreme. Also, he designed an improved fitting mask based on 3M’s R-6311 respirator body.

An advance, but once again, improvement was needed. On my descent from the summit of Everest in 2011, the tube going to my TopOut mask froze, shutting off all oxygen to my mask. Of all places to occur, it was on the Hillary Step where I was exerting all my remaining strength to get down safely. Thankfully, the Sherpa I was with, Kami, rushed to my aid as I reached the base of the Step where he punched the frozen hose with a solid right fist.

For 2013, Atkins moved the flow indicator and controller from the regulator attached to the oxygen cylinder located in the climber’s pack to an in-line device within the delivery tube, allowing for easier adjusting and monitoring by the climber. He also added a shorter tube connection to the bottle to address the freezing problems.

Sadly, Ted died in August 2018 while rock climbing in the Dolomites. His Nepali business partner Asian Trekking took over operations and currently sells the system.

Summit Oxygen

Summit Oxygen Mask

Summit Oxygen Mask

Another UK company once again redefined the oxygen delivery technology. Neil Greenwood’s Summit Oxygen entered the market in 2003 with an actual on-demand system that used tubes directly into a climber’s nostril, similar to a hospital environment. It was used then and today in military applications, but the flow was insufficient to meet the demands above 8000m for the typical Everest climber. They needed a system that provided more of a steady flow.

Greenwood shifted to the more traditional system for climbers with a more conventional mask, regulator, and cylinder. He designed an entirely new system and has continued to make incremental improvements. They offered a complete cylinder system, valve, regulator, and mask in the lightest weight system on the market. I used the Summit Oxygen systems successfully on Manaslu and K2.

In 2019, several teams experienced regulator failures near 8,000-meters. Thankfully they had replacements or dealt with it successfully that there were no casualties. At the time, Greenwood felt it was a combination of humidity, temperatures, and a slight manufacturing defect that lead to the failures.

The Austrian guide company, Furtenbach Adventures took over Summit Oxygen in 2021. Furtenbach is investing to allow regulators to flow at higher rates, up to 8 lpm, plus other improvements.

Costs and Quantities

Pricing is fairly consistent across all suppliers, with a bottle costing about $400, a regulator about the same, and a mask $300. Using the standard bottle that holds 720 liters of oxygen (and weighs in at almost 5 pounds), breathing at 2 lpm will last about six hours. Doubling the flow to 4 lpm, it’s gone in 3 hours. Sherpas usually run at 1 lpm; thus, they only use one bottle for 12 hours on the summit push.

Members usually start using supplemental oxygen at Camp 3 around 7,000-meters though some are now starting at C2. One bottle takes them from C2 to C3 or C3 to C4, aka the South Col, where they rest on the remaining supply until they leave for the summit. A full bottle takes the climber to the Balcony, where a fresh bottle is swapped, and the half-empty bottle is cached for the return to C2. Thus, most climbers running at 2, 3, or 4 lpm will use three or four bottles, but most expeditions assume five or six bottles per client. For all the bottles plus the mask and regulator, look at $3,000 to $4,000. This is usually part of a legitimate Everest guide company’s package.

Many members will opt for the “extra oxygen” program where they run at a higher rate, using more bottles and swap out at both the Balcony and the South Summit. Of course, it requires humans to get the bottles where they need to be, so this option requires another Sherpa adding $6,000 or more for the Sherpa plus oxygen to the base level of the expedition price. Note some charge as much as $10,000 and require more bottles for the Sherpas.

Who is Trying without O’s in 2021?

On Friday, April 23, Nepal had issued 394 permits to foreigners, and it will go even higher. Only 11 have said they will not use supplemental oxygen. So, who is not using supplemental oxygen this season?

  1. Pascal Denoel (normal route)
  2. Alex Chikon (normal route)
  3. David Goettler (normal route)
  4. Csaba Varga (normal route)
  5. Alex Txikon (normal route)
  6. Sanna Raistakka (normal route)
  7. Roeland van Oss (normal route)
  8. Arjun Vajpai (normal route)
  9. Simon Ferrier-May (normal route)
  10. Kilian Jornet (Everest-Lhotse traverse via the West Ridge.)
  11. Colin O’Brady (Everest-Lhotse)

As you can see, all but Kilian will be on the normal route, which may be problematic with the super huge record crowds. They will either go early or late to avoid the masses. One of the problems climbing without O’s is staying warm, and you must be moving to aid in this area.

Why No O’s?

It often comes down to one word, style. Many purists in the mountaineering circles feel that the only proper way to climb a mountain is by so-called “fair” means. That definition can be used in many ways to obtain sponsors, claim records, or, more significantly, to feel good about their effort.

Does it make a Difference?

Absolutely. I can tell you from personal experience that O’s keep you warmer, help minimize the chance for frostbite and allow you to move faster. That said, I took off my mask for many minutes on the summit, and on K2, will no ill effect (at least I think not!)

Are O’s a Drug?

It depends on who you ask. Lukas Furtenbach of Furtenbach Adventures has unique regulators that allow his members to run at 8 liters per minute at times, not all the time but when needed. Plus, he has special technology for a remote doctor to continuously monitor a climber’s oxygen saturation and make necessary oxygen flow adjustments. Most people will use two to four lpm, and some will go up to six, but four is the standard amount. Lukas feels that if you are going to use O’s, the level doesn’t matter, so use as much as you need. It views it as a safety issue.

But the purist will say that even if you put on a mask for five minutes, your no O’s climb is void. You cheated and used a PED – performance enhancing-drug. Don’t even try to argue this point. The purist made up their minds in the last century and will never move.

What do you think of climbers who use supplemental oxygen on Everest?

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The Science

There are multiple excellent articles describing what happens to our bodies at altitude, but we are dying to over-simplify it. These are good references for more details plus some interesting research that mountain altitude may not be what you think it is depending on the season.

The Stats

Of the 304 deaths on Everest, 170 or 55% were not using supplemental oxygen and of those, 110 died on the descent.

Of the 279 deaths who were climbing Everest, i.e., not at base camp or elsewhere, 146 or 52% were not using supplemental oxygen, and of those, 110 died, or 75%, on the descent.

Here is more data than you want 🙂 Of note, Everest is getting safer, even for those not using O’s, down from 42% in the last century to 28% in this one. Thank weather forecasting and improved clothing and gear technology for this!

Members Only1923-20201923-19992000-2020
Total Summits5,148
No O's1577582
% No O's3.05%9.5%1.88%
Total Deaths1769581
Deaths No O's634023
% Deaths No O's36%42%28%
Deaths with O's1095158
% Deaths with O's62%54%72%

Permits – Record!!

The permits for Everest surpassed the previous 219 record of 382. The Nepal Ministry of Tourism posted these foreign permit tally as of April 23.

    • Everest: 394 on 42 teams (400+ expected)
    • Lhotse: 104 on 11 teams
    • Nuptse: 23 on 3 teams
    • Manaslu: 1 on 1 team (over)
    • Annapurna: 44 on 4 teams (Over)
    • Dhaulagiri: 33 on 5 teams
    • Pumori: 9 on 2 teams
    • Makalu: 20 on 2 teams
    • Ama Dablam: 27 on 2 teams
    • Tukuche: 1 on 1 team
    • Tilichho: 8 on 1 team
    • Tengkangpoche: 2 on 1 team
    • Baruntse: 12 on 1 team

The Tibet side is closed to foreigners, but there are 40 Chinese nationals reported now at base camp.


Some of the Annapurna summiters are moving to Dhaulagiri. They will have to take another COVID test before being allowed to go to Dhual. The route fixing on the normal route has reached C1. Among the climber is 82-year-old Carlos Soria is on this 12th (yes, twelfth) has arrived at Dhaulagiri Bas Camp after trekking in the Khumbu for acclimatization. He only has it and Shishapangma to complete climbing all fourteen of the 8000-meter peaks.

Esteban “Topo” Mena gave this update:

Missing these views from Dhaulagiri C1, but for now just focusing on getting all the 🔥 ready for a summit attempt next week!!!  The last couple days have brought a lot of fresh snow and uncertainty regarding conditions up high… regardless of what hand we gonna be dealt next week, there is just one thing we can control now: to be as ready and stoked as possible! These days are all about channeling our inner himalayan monkeys!

The Slovak-Romanian team lead by Peter Hamor with Marius Gane and Horia Colibășanu has made progress on their attempt at the North-West ridge and then descend along the North-East ridge.

Follow Along!

Visit my annual team location table and tracking climber’s blogs (see sidebar) to see where everyone is perched. If you have a team not listed, please let me know, and I will add them if I can track them. If you prefer not to be mentioned, please contact me.

Climb On!
Memories are Everything


The Podcast on

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  2 Responses to “Everest 2021: Will Record Everest Permits Put the No O’s Climbers at Risk?”


    Using Oxygen and extreme comforts in base camps are very country cultural specific . Some cultures are much more ” the Goal justifies the means” focused.


    If you’re summiting with the use of top-of-the-line clothing, boots and climbing gear, all reasearched and developed in the 21st century with cutting edge technology, well….that’s not very ‘pure’ either, is it?

    A truly pure summit would surely be done wearing a yak coat and using a stone pickaxe.