Cho Oyu Expedition


Climbing Style


Cho Oyu from the SSE, near Gokyo Ri.
Photo Mark Houston

By private arrangement
$15000 per climber (includes oxygen)

3:1 climber to guide maximum

Group Size:
Maximum 6 climbers with 2 guides


Cho Oyu, at 8201 meters, is the sixth highest peak in the world and, of the 14 peaks over 8000 meters, has the highest success rate. Because it is perhaps the easiest of the 8000 meter summits, it is quite popular and there can be many expeditions on the mountain at one time. The normal (Tichy) route climbs from the Tibetan side.

The peak is commonly climbed in both the pre and post-monsoon season. Most expeditions allow about 6 weeks, Kathmandu to Kathmandu. The spring season schedule normally has climbers beginning their expedition in the first 2 weeks of April, and finishing it in the last 2 weeks of May. The fall season starts in early September and runs to mid-October. Success rates are similar in either season.


The trip begins in Kathmandu. After a rest sightseeing day there we begin our drive into Tibet. We take a rest day in Nylam to acclimate then continue to the old Chinese Base Camp in two more days. This camp is about 15 miles from Advance Base Camp (ABC) which is reached in two days of trekking. We establish 3 camps above ABC. Camp 1 (21,000') is reached by trail in dirt and scree. Normally, trekking shoes are the only footwear needed for this section. Camp 2 (23,000') is on the upper glacier plateau. Between 1 and 2 is a section known as the Ice Cliff. This steep ice climbing part is equipped with fixed rope and requires some steep frontpointing. Camp 3 is at about 24,400' and located on a gentle slope. Above the summit day climbs through some easy rock bands (normally fixed) to the broad summit.

Planned itinerary - More details on the itinerary

  • Day 1 Depart US
  • Day 2 Arrive Bangkok, overnight
  • Day 3 Arrive Kathmandu
  • Day 4 Organize in Kathmandu
  • Day 5 Drive to Zhangmu (7,500')
  • Day 6 Drive to Nylam (12,300')
  • Day 7 Acclimatize in Nylam
  • Day 8 Drive to Tingri (14,800)
  • Day 9 Drive to Base Camp (BC) (15,700')
  • Day 10 Rest in BC
  • Day 11 Trek half way to Advance Base Camp (ABC) (16,900')
  • Day 12 Arrive ABC (18,400')
  • Days 13-39 Climbing days (27 days)
  • Day 40 ABC to BC
  • Day 41 Rest in Chinese Base Camp
  • Day 42 Drive to Kodari, Tatopani, or Zhangmu
  • Day 43 Drive to Kathmandu
  • Day 44 Rest in Kathmandu
  • Day 45 Depart for UD
Cho Oyu
Photo Mark Houston

Climbing Style

The style of climbing normally used on major Himalayan peaks is often different than that used on traditional Alpine climbs. The most significant difference is the increased use of fixed rope on difficult sections and the consequent reduced amount of time climbers spend roped together. On most parts of the climb, climbers travel individually and unroped. Where the steepness warrants, fixed roped are placed for protection. While this style of climbing carries other hazards and a high level of self-reliance and responsibility, it also permits greater freedom of movement and an ability to travel at a pace more individually tailored.

We have tired to keep our group as small as possible and still make it economically feasible. We would like to be able to climb with you and be with you, rather than sit in Base Camp, monitoring your actions on a radio. Many expeditions are so large that the leaders find their most valuable role as master puppeteer, managing the team from below. Our goal is to have a more personal involvement — being with you to help you achieve your objectives with as much vigor as we can muster. While we expect that for much of the climbing on the peak we may not be directly roped to you, we do hope that our small group size will permit us to travel roped where we both feel it would be advantageous to you.

Sherpa Support

We are planning on having Sherpa support for moving group gear, setting up camps and helping in other ways. Typically we will have one Sherpa per 3 climbers (including guides). We can arrange additional individual Sherpas to help for about $3200 per Sherpa.


Cho Oyu is frequently climbed both with and without supplemental oxygen. The use of oxygen significantly decreases the chance of developing health problems, and, to some extent increases odds of summit success. For most climbers, and certainly for those who have not climbed to this elevation before, we recommend its use. We are planning on using Russian systems, which are popular with many Himalayan expeditions. We have budgeted 3 bottles plus mask and regulator per person. The bottles hold about 1200 liters of oxygen. This amount lasts for about 10 hours at 2 liters per minute, a rate commonly used for climbing. For sleeping, a rate of .5 liters per minute helps to get more sound rest. Normally oxygen is used for sleeping at the highest camp and for the summit climb. Three bottles per person should be enough for two summit attempts. This amount of oxygen is somewhat more than is normally allowed for, but we feel that it increases the odds of success. Please note that the bottles, empty or full, must be carried back down the mountain and we expect team members to be responsible for this.

Many climbers on Cho Oyu (perhaps most) choose not to use bottled oxygen. They make this decision for several reasons. The cost for the oxygen is significant — a mask, regulator and 3 bottles cost upwards of $1800. The use of oxygen introduces an additional level of complexity, and a reliance on not infallible technical equipment. Some climbers feel that its use violates some sort of "fair means" ethic. Some simply would prefer not to use oxygen feeling that the rewards of an oxygenless ascent justify the increased risk and greater difficulty of the ascent. Though the current technology is very weight efficient, the use of oxygen does require that additional equipment be brought up and down the mountain.

We discussed long and hard about the possibility of climbing without supplemental oxygen. In the end we felt that we could not justify the much greater health risks. While some of these problems may be minor and simply keep you from the summit, others are life threatening, specifically those related to pulmonary and cerebral edema. Even simple head colds can develop into very dangerous health hazards.

At a minimum we would like all climbers on our trip to have access to oxygen for sleeping and for the summit climb.

Radios and other equipment

We will have radios for communication between camps and plan to have emergency oxygen and a hyperbaric chamber (Gamow bag) at Advance Base. The emergency oxygen is fairly heavy equipment and is not suitable for climbing.

Mark & Kathy 17 years ago with Cho Oyu behind.
Photo Mark Houston


Trekkers can join us on this trip and can climb to Camp 1 at 21,000'. The terrain up to this point is often ascended with only minimal footwear and is non-technical. The area around advance Base Camp offers only limited hiking possibilities and we suggest that trekkers plan on other activities and visits to other places (such as Lhasa) during our climb. We can have our agency in Nepal, Windhorse Trekking, work out possible itineraries and cost for you if you.

Our Agency in Nepal

Virtually all expeditions to Cho Oyu originate in nearby Kathmandu. And all of them involve the support of an agency there. Our agency is Windhorse Trekking, a company run by Ang Karma Sherpa. We first met Ang Karma some 16 years ago on our first trip to Nepal where he joined us for our trek into the Khumbu area. At that time we were working with his brother Kunga Sherpa and his agency. On subsequent trips to Nepal we continued to work with Kunga, while keeping loose contact with Ang Karma. Unfortunately, Kunga died not long ago and we again renewed our relationship with Ang Karma. In the years since we first met Ang Karma, he has risen steadily in the hierarchy of the Nepalese Mountaineering Federation. Until last year he served as its Hon. General Secretary and not long ago he was nearly elected President. Ang Karma has written several guide books on local Kathmandu climbing and is ever busy with one project or another. His English is probably better than ours is and he is a very fun person to spend time with. We can't think of a better person to shepherd us through the logistical requirements of putting together an expedition to an 8000-meter peak.

Windhorse Trekking has a web site at if you would like more information about Ang Karma or his company.

Who should come?

We are looking for 5 or 6 climbers to join us. While all of us are different and each brings his or her own special contributions to a trip such as this, there are a few qualities and characteristics we should all share.

Fitness — Cho Oyu, like any big mountain requires a very high level of fitness, and this is one of the most import features of successful expedition members. Aerobic fitness is key. We all measure our level of fitness in different ways and it is sometimes difficult to compare. In general however, you should be able to ascend over 5000 vertical feet in less than 4 hours, including rests and stops, carrying a 20-pound pack.

General health — You should be in good general health. High altitude climbing is hard on the body, and any little problem can often grow into a big problem.

Patience — You need to have a good deal of patience to deal with the inevitable setbacks that come with a trip as long as this one. Over the years we have found that a patient attitude consistently brings the best rate of summit success. On extended trips there are always problems that crop up, commonly health and weather/conditions. Though it may not seem like it at the time, these problems are usually transient and a patient climber will better be able to psychologically handle these temporary setbacks.

Team player — Expeditions are very much a group activity. None of us are saints, but we do need to work together to get the needed equipment up the hill (and down again) and ourselves into position to summit. In addition to helping with group related tasks, we recognize the need for individual space and the need for personal conservation of strength and energies. Finding the right balance between "giving all for the greater good" and conserving everything you have for your own summit attempt can be difficult. Even so we hope that climbers will understand why each of us is here and respect and support our individual and group goals.

Technical ability — Technical climbing ability is not of great importance on Cho Oyu. Cramponing skills are essential, and experience with steeper ice is necessary to manage the short but steep fixed Ice Cliff between Camps 1 and 2. More important than high-end steep skills is that group of skills necessary to walk with great efficiency on moderate ground. You should be comfortable in crampons and be able to walk mindlessly, and with very little additional energy expenditure, up and down 30 degree slopes. The more experience you have with easy but rough terrain the less energy you will expend in climbing it.

Experience at altitude — Cho Oyu is a good choice for your first 8000 meter peak. Climbers with illness free experience on peaks such as Denali or Aconcagua are ideal candidates. There is considerable debate on the relative value of having previous climbing experience to 6000 meters on other peaks. Some argue that 8000 meters is a whole other ball of wax and that trouble free ascents on peaks of lesser altitude don't mean much. Others say that climbing to 6000 meters and above previously at least indicates an ability to go that high. Probably more than 95 percent of healthy individuals can acclimate successfully enough to climb Denali or Aconcagua. So unless you are one of those unlucky (lucky?) 5 percent then a climb of a 6000 to 7000 meter peak really won't tell you much about your ability to climb Cho Oyu. If you acclimate normally and have experience to over 6000 meters, you should consider the trip. If you lack such experience but have felt hale and hearty on 14000 and 15000 foot summits you should discuss the options with us, but odds are you will be OK. If you have had trouble acclimating or have no experience to 14000 feet you should get more experience before joining a trip to such high altitudes.

Self reliance — As we mentioned above, climbing on 8000 meter peaks is often undertaken unroped in the traditional Alpine sense of the word, but with the additional security of fixed ropes on steeper sections. You need to be comfortable managing ascenders and rappel devices independently, even in times of near exhaustion. Likewise you will need to manage and monitor your oxygen usage and equipment. Perhaps most important, however, you will need to be keenly attuned to your health, level of acclimatization, and energy levels.


Cho Oyu Expedition Fees

5 or 6 climbers with 2 guides
(includes oxygen)

Approx. $ 15000 per climber

Program Cost Inclusions

  • Kathmandu Hotel 3 nights, shared, w/breakfast
  • Lodging on drive to base Camp
  • Food for trek, BC and climb
  • Sherpa support,1 per 3 climbers
  • Cook, kitchenboy, porters and pack animals
  • Airport/hotel/airport transfers
  • Climbing permits
  • Group climbing equipment
  • Tents for BC and climb
  • kitchen/dinning tent, toilet tent, chair/tables
  • Oxygen for medical emergency
  • Transport Kathmandu to Chinese Base Camp and return
  • Approximately 3600 liters O2 for sleeping and summit climb
  • Gamow bag access in Base Camp
  • Radios for communication, 1 per camp
  • UIAGM / IFMGA and AMGA certified guides, Kathy Cosley and/or Mark Houston

Program Cost Exclusions

  • Meals in Kathmandu,
  • Visa fees, Nepal and China
  • Airfare to and from Kathmandu
  • Personal equipment
  • Airport departure tax
  • Kathmandu hotel beyond the 3 nights covered
  • Tips for staff
  • Insurance
  • Items of a personal nature

Sign up for this expedition - Please contact us


Kathy Cosley & Mark Houston
UIAGM Internationally Licensed
Mountain Guides

AMGA Certified • SNGM members

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