Introduction
The Cerro Aconcagua is one of the seven summits and with 6960.8 meters the highest mountain outside Asia. Depending on the different pre-columbian cultures that were present in the region like the Inkas or Mapuche, the meaning of the word Aconcagua is guessed to be “stone guardian” or “snow mountain”. Climbing Aconcagua is a challenging task, that needs good preparation and experience. Even though the normal route to the summit is known to be non-technical, the weather conditions and extreme altitude make the climb dangerous and demanding, leading to a comparatively small amount of people who actually reach the summit (about 30% of all attempts succeed) and causing multiple accidents and fatalities every year. I climbed Aconcagua in 2023 and want to give an overview and details about how to prepare for a Solo approach and what to expect from such an expedition. I especially want to make the point that this mountain should not be underestimated! A careful preparation is necessary and a lot of investments — monetary, but also physically and mentally — need to be done, to have a chance of reaching to the summit.
The article is structured as follows. I first want to give a short insight into the fundamental logic of increasing your success probabilities that should be considered for such expeditions and influence all other parts of your planning. I then give insights into the more practical parts like the permit acquisition, Base Camp services and infrastructure, equipment and considerations for the acclimatisation, weather forecast and strategies for the choice of the high camps based on my experiences.
Increasing your Success Probabilities
First of all I want to write about something that most reports do not cover. The probabilities of reaching the summit. I mentioned in the introduction that only 30% of all attempts actually end up at the summit. This is not only because too many people go unprepared to Aconcagua, but also because in reality a lot of factors need to be in line to actually have a good chance of reaching the summit. Almost 7000 meters of altitude are not a joke — if the acclimatisation is not perfect one most likely needs to turn around, and you also put your life at risk. Moreover the temperatures at the summit can go down to -30°C, together with winds of up to 130 km/h, the felt temperature is about -50°C. This means that you can easily freeze your nose, toes, fingers, etc. A lot of people have to turn around in order to safe their extremities because the weather is to brutal or the equipment not sufficient. All these factors will in the end determine how high are your chances of reaching the summit. It is not only about your physical preparation, or your equipment — it is also about how well your body adopts to the altitude, a good timing, strong will and luck with the weather. Also it should be considered that if you have to spend a long time at the Base Camp you have to take a lot of care to keep your body strong, by bringing good food and sleeping warm enough. A long waiting time will also decrease your physical performance but too less of a time and you might not acclimatise well enough. The same counts for the selection of the high camps. The higher you go, the more you will weaken your body, but the better (usually) is the acclimatisation. You have to find the right balance. Here is a list of the factors to consider:
From all the factors, the acclimatisation and weather conditions are most important. Especially during bad weather, most expeditions fail as it is basically too cold and dangerous to go to the summit. In the end you have to maximize some of the factors and find a good balance between others to increase your chances. With perfect equipment you are more likely to reach during bad weather and with more time you can acclimatise better but also need to consider that your physical strength might decrease.
Permits and Base Camp Services
Permit Costs
In 2023 the permit costs for Aconcagua were 800 $ (For non latin american people). To my knowledge there is no discrimination between pre and high season climbs anymore (correct me if this is wrong). I booked the permit via one of the companies providing services at Aconcagua, who did not charge extra fees. It is advisable to do that, as the application process for the permit seems to be very intransparent and information are barely available. You need to provide some personal information and a rescue insurance is mandatory. I heart that some people payed more than 400 $ only for the insurance. There is definitely cheaper options! A membership in the german alpine club for example includes a rescue insurance that is explicitly valid for the Aconcagua normal route (costs of the membership are about 60 $ per year). Something similar exists in France, so it is worth doing some research on that. After acquiring the permit from a company you can pick it up in Mendoza and some companies provide you with their basic Base Camp services if you acquired the permit through them. Important to know is also that you can get an early bird permit price if you acquire the permit before June in the ongoing year in combination with some other service of a company (for example Mule Rental).
I don’t know how you can do the permit application by yourself (without any company), if this is possible at all and if it would be cheaper. From my perspective it is best to do the application via a company as it is more secure, saves you time in Mendoza (otherwise you have to do the whole application process in Mendoza) and you acquire the Base Camp services.
The National Park Infrastructure
The permit is expensive but also comes with some advantages. You enter the national park at Horcones (make sure to arrive there before 5 pm) and register at the park officials. They will give you a white and a red plastic bag. The white one is for your normal trash the other is for human waste. Before leaving the Base Camp you can give the respective bags to the company that you acquired the permit with (again — if you acquire the permit by yourself I don’t know what happens then), they will sign your permit and you can successfully exit the park again.
Moreover you have registration points at Confluencia, Plaza de Mulas and Nido de Condores, so that there is always some people knowing where you are. At the same camps you can also do medical checks (e.g. oxygen saturation) which is very recommendable. Finally there is a helicopter evacuation available for the case that your physical state is very bad. To my knowledge the highest camp that the helicopter reaches is Nidos the Condores.
Pre Season: Even though the permit price in the pre season is not cheaper there is barely any services in November. Most park officials only enter the park after the beginning of December, there is no medical checks and no helicopter evacuation!
Base Camp Services
If you buy any service with one of the companies (Mule Rental, Permit, etc.) you also get the basic Base Camp services. These include a spot for your tent in the area of the chosen company, drinking water, toilets, electricity, weather forecasts and access to one of the larger tents to prepare and eat your food (here you will also meet most of the other “Solo-Climbers”). I don’t know if it is possible to climb without having these services, as it would be difficult to find a place for your tent and especially drinking water at the Base Camp is very scarce and the companies normally use sources that are a little bit further up to assure good water quality. I also think administratively you need to cooperate with some company for the permit and your waste disposal.
The water quality at the Base Camp is usually good but if you want to be safe, bring a filter or chlorine tablets to purify the water — poisoning yourself with some germs is the last thing you want up there — for the same reason also bring hand disinfectant.
Mule Rental
Renting a Mule, so you do not have to carry all your luggage (with food usually between 30–40 kg) the whole way to the Base Camp is recommendable in order not to totally exhaust yourself before the actual climb. The price policy for most services are also quite intransparent and it is best when you ask your company three times what is included in a given package. I payed 200 $ for a Mule to carry my luggage to the Base Camp, but the way back was not included, while I met some other people who payed 250 $ for both ways. The maximum weight per person is 30 kg. Also: respect the Mules, they are definitely having one of the hardest job in the whole area and are often not treated very well.
Other Services
As you are probably trying to make the climb as pure and self made as possible I do not describe other services here. In general you can get everything at the Base Camp (showers, food, wifi,…) — but for a high price. Wifi costs about 30 $ for 500 MB (different companies have different services, meanwhile they also installed a star link connection (with the company Grajales). You need to be aware that most of the services will not be available at the beginning of the season.
Bus Transfer Mendoza
There is a bus from Mendoza to Penitentes (where you usually deposit your luggage for the Mules) or Horcones (where you enter the park). It costs basically nothing and leaves two times a day. The company is called Andesmar, you can book tickets online and at the terminal in Mendoza — book them earlier as they are usually pretty occupied. Taking the later bus at 10 am is still sufficient to have enough time to enter the park and reach to Confluencia.
Companies overview
Finally here is a (incomplete) list of the different companies that operate at the Base Camp. These companies provide all the infrastructure available in the Camps. They offer guided tours themselves but also cooperate with external guides and groups and provide them infrastructure services. I guess everyone who wants to climb Aconcagua has to cooperate in some form with a company for the climbing permits, waste management, Base Camp services or Mule rental. As mentioned before I don’t know if it is possible to climb totally without a company. These are the largest companies:
Equipment
Your equipment is especially important to protect you from the hard weather conditions — the technical functionality is not really important. If you only have a short time to get to the summit, a good equipment is very important as you might not be able to wait for a perfect weather window. During good weather you can actually go to the summit without very big jackets and large boots — but in any case such conditions are rare and can always change — so for a secure ascent good equipment is absolutely necessary.
You have the chance of renting equipment in Mendoza — in my opinion the prices are pretty high and you are better of buying at least some of the things yourself. The rental equipment is not bad but in some cases can be pretty old and therefore not sufficient for bad weather conditions. Here are some stores that rent equipment, some of them cooperate with the expedition companies and can give you a discount when you have booked some service with the given company.
In the following are some comments on the most important equipment:
Double Boots: Good double boots are crucial to not freeze your toes on the way to the summit. The most common shoes that you see on the summit are from La Sportiva like the G2-Evo. In order to get your feet even warmer you can put two layers of socks and buy chemical toe warmers. Also it is crucial that the shoe fits very well as double boots are not very comfortable in general (like walking in ski boots) and extra pain in you feet or chins make the summiting unnecessarily harder. Another tip for the double boots is to already wear the inner layer in the sleeping bag before the summit night in order to safe the heat of your feet.
Sleeping Bag: You should bring a sleeping bag of at least -20°C comfort, better -30°C. Especially if you decide to sleep in Camp 3 (6000 meters) you can expect temperatures that low. Also it is crucial to always keep you body warm in order not to catch a cold while waiting in the Base Camp.
Gloves: Suitable down mittens are necessary in order to protect your fingers from freezing. Also put hand warmers and get linen gloves for inside. If your down mittens are not very thick it is recommendable to put at least one other layer on top as a wind shield (you can find those in the rental stores).
Tent: Your tent does not necessarily need to be from North Face but you should have a stable construction that can withstand strong winds (no tunnel tent). Small tents with crossed aluminium poles can be sufficient, but always find a good shelter or build a stone wall to secure everything properly.
Body Layers: To keep your body warm enough during the summit day you need at least one very good down jacket, a wind shield and multiple layers of functional clothing below. I went with a thermo shirt, fleece, s small wind breaker from patagonia and two thick down jackets. For the legs it is recommendable to also get down pants and a wind and water resistant upper layer. Finally it is important to have sufficient coverage for your face, especially also the nose to not get frostbites from the strong winds. Also bring skiing goggles to protect your eyes.
Technical Equipment: Depending on the time of the season and the weather there might be some snow fields at the Traversia and the Canaleta might have some frozen parts where it is advisable to bring crampons, and if you want to be save, also an ice axe. Also there could be stones coming down in the Canaleta during day times so a helmet is advisable as well — be aware that it needs to fit good below the hood of your jacket so you are not loosing temperature because of wearing the helmet.
Gas Stove: Bring a gas stove that is efficient for melting snow, otherwise you spend hours melting snow in the higher camps. When melting snow it is important never fill the whole pot with snow, as snow is a good insulator, so you could burn the lower part of your pot when the heat is blocked by a thick snow layer. It is best to fill a plastic bag with snow bring it into your tent and then melt it step for step until it boils. Also bring some salt to put into the water as melted snow is basically like drinking distilled water.
GPS or Radio: If you are totally on your own it is advisable to bring a radio or a GPS device with emergency function. Garmin offers a device for satellite communication that is comparably cheap and allows you to send messages directly to the phone of friends and family. Otherwise you can get a radio in order to have local communication with your company or the mountain police. Remember that the summit is very remote — if something happens there and you have no means of communication a fast rescue will be very unlikely.
A full list of the equipment that you must bring is given at the end of the article.
Acclimatisation
Basics on Acclimatisation and Altitude Sickness
There are no predetermined factors that are proven to increase or decrease the risk of getting altitude sick. So if you decide to expose your body to extreme altitudes as at Aconcagua, it is smart to have further experience in other regions to know how your body reacts. Otherwise the expedition can end already at the Base Camp and the spent money is kind of wasted.
The oxygen concentration in the air at low and high altitudes is about 21% but with increasing altitude the partial pressure decreases due to the lower weight of the atmosphere, leading to lower availability of oxygen. Closer to the poles the atmosphere is thinner compared to the equator so the oxygen pressure is even lower. This is because at the poles the air is colder and therefore thicker. As the gravitational force does only vary marginally globally, and therefore the air mass that are attracted to earth before escaping into space are similar, the result is a smaller atmospheric thickness. In the troposphere (atmospheric layer) the partial pressure drops linearly with increasing altitude and therefore the partial oxygen pressure at same altitude is smaller close to the poles compared to the equator.
For example: Aconcagua is at a latitude of 32° South, Denali at 63° North and Everest at 27° North. So even though Denali has a comparably low altitude (~6100 meter), due to its high latitude the acclimatisation is comparable to Aconcagua (~7000 meter). Other factors that influence the partial oxygen pressure are weather systems, temperature and humidity.
Due to the reduced oxygen concentration your body undergoes a series of changes to adapt to the new environment that are starting after a couple of hours and can last for several weeks. As one of the first changes your blood volume decreases in order to increase the oxygen concentration, which leads to an increase of your heart rate. Also your ventilation rate increases to increase the partial oxygen pressure in the lungs. This has the side effect of a higher expiration of CO2 and therefore a higher pH level in your blood, known as respiratory alkalosis. The body tries to balance this out by eliminating alkalic molecules which leads to increased urination. This is one reason why it is important to drink at least 3–4 L a day at high altitude.
An increase in the red blood cells is initiated as well by a release of Erythropoetin (EPO) into the blood stream. Moreover the release rate of oxygen from hemoglobin to the body tissues is increased significantly. This adaptation still needs a couple of days to be effective.
A very detailed overview of acclimatisation processes are given in this article:
All the adaptation processes and the lack of oxygen lead to symptoms like headache, dizziness, short breath, disturbed sleep, etc. As long as the symptoms are mild, a slow ascent can be continued. Also Diamox can be used as a preventive medication to reduce altitude symptoms — still a slow acclimatisation process is always required.
If symptoms become more strong a fast descent is required. The worst forms of altitude sickness are lung or celebral Edema, caused by fluid buildups, that can be deadly and develop very fast at high altitudes.
In Nidos de Condores (High Camp 2) they have a Gamow Bag during high season which is like a small tent in which low altitude atmospheric conditions can be simulated in order to treat high altitude Edema.
Acclimatisation Strategy
After this short dive into the effects of altitude on the body it should be clear that a proper acclimatisation is crucial to ascent Aconcagua safely and successfully. Most guided groups normally have the following itinerary to provide good acclimatisation. In my point of view this is too short, to ensure a proper acclimatisation:
Day 1 — Mendoza (600 meter)
Day 2 — Confluencia (3400 meter)
Day 3 — Confluencia, Acclimatisation to Plaza Francia
Day 4 — Base Camp (4300 meter)
Day 5 — Base Camp rest day
Day 6 — Base Camp, Acclimatisation to Cerro Bonete (5000 meter)
Day 7 — High Camp 1 (5000 meter)
Day 8 — High Camp 1, Acclimatisation to High Camp 2 (5500 meter)
Day 9 — High Camp 2
Day 10 — High Camp 2, resting or Acclimatisation to High Camp 3 (6000 meter)
Day 11 — High Camp 3
Day 12 — Summit (7000 meter)
While this can be sufficient for some people, other might not be able to acclimatise that fast. Of course this is also a matter of time. If you are lucky and got more than two weeks time it is advisable to already start acclimatisation before coming to Mendoza. I spent 10 days in Sajama (Bolivia) a village at 4000 meter, where you still have infrastructure and even the possibility to hike some 6000 meter volcanos. As previously described, the longer the acclimatisation, the higher your chances of actually reaching the summit.
Weather
The weather at Aconcagua is what makes the mountain very unpredictable and dangerous. This website gives a good overview of the weather system at Aconcagua:
The weather at Aconcagua usually comes in cycles and normally you have stable conditions every 3–5 days during the summer season. Weather during January and February is best but these patterns are not reliable anymore with climate change. The season 2022 for example had excellent weather in November, while in 2023 when I arrived at the Base Camp we had an unusually long period of strong winds and very low temperatures. Most companies use the mountain-forecast webiste to check weather conditions:
The website provides a lot of useful information, like the windspeed, precipitation, temperature and — even more important — the chill. The windspeed on the website is given for the gusts, therefore other weather services often forecast way lower wind speeds.
To get a feeling what are considered good weather conditions, here are some remarks on that. The numbers are given for the summit and wind speeds are in gusts. A temperature at the summit of about -20°C is considered pretty comfortable if the wind speed is below 50 km/h, resulting in a chill of about -30°C to -40°C. This would be very good conditions to go to the summit. Winds between 60–80 km/h can still be fine but with winds above 80 km/h the risk of frostbites is already very high and you definitely need good equipment and already have some experience of how well this equipment works in extreme conditions.
When I was at Aconcagua a couple of groups tried the summit at a day of -25°C and winds about 80 km/h. Most of them had to turn around and only two US guys made it to the summit, one of them getting major frostbites at the nose. Also at a day of strong winds above 110 km/h (in gusts at the summit) a couple of people had to descent from Nidos de Condores because they got frostbites — so be aware that also at the High Camps extreme conditions can occur and be dangerous.
The High Camps
This virtual map provides a good overview of the normal route and the Base Camp:
After the Base Camp you have the choice between four different High Camps to reach to the summit: Canada at 5000 meter, Nido de Condores at 5500 meter, and Berlin and Colera, both at roughly 6000 meter. Depending on the wind direction, Canada can be pretty exposed. Nido de Condores is a large plateau that is therefore also pretty exposed to strong winds. Here you find some infrastructure like park rangers, mountain police and a medical service (only after beginning of december). Most of the companies build larger dome tents and even toilets here (all of that are not supposed to be used by solo climbers). Interestingly for some wind directions Nidos de Condores was pretty calm (I did not note exactly which ones).
Berlin and Colera can both be chosen as a last High Camp before the summit approach (Colera is a little bit higher than Berlin, and about 15 minutes walking distance from Berlin). Berlin has the advantage of being better protected from the wind. Also there is two small shelters that can be used in emergencies. When I was there they were full with snow. Colera on the other hand is used by all the companies and also contains some dome tents. Have in mind that conditions in Nido de Cndores, Colera and Berlin can be really rough compared to the Base Camp!
In my opinion the best strategy to reach the summit is to start from Nido de Condores and not from Colera or Berlin. Depending on your acclimatisation you can go directly from the Base Camp to Nidos de Condores, spent two nights there and then make a summit attempt (this is how I did it, but after a long time of acclimatisation in Bolivia and the Base Camp). You need to consider that in the higher camps you are more likely to loose energy that you need for the summit day — most people that go to Colera do not really sleep there. So it is a trade off between acclimatisation and physical fitness that you need to balance wisely.
The Summit Day
I finally want to give a short overview of the summit day and what to take care of. On the normal route of Aconcagua it is not necessary to start specifically earlier for melting ice and increasing danger of falling rocks. Most groups start at Colera at 5 am to avoid walking to long in the cold of the night and loosing body warmth. In the end you can also decide depending on the weather conditions. If the morning hours still seem to be very bad and a weather change is expected during the day you could even shift the starting time a little further back. For the summit day try to already put all or most of your layers in the sleeping bag — also the inner part of the double boots. You need to put crampons, ice axe (not mandatory), helmet, walking poles, minimum 3 L of water and enough snacks as well as first aid set, emergency biwak, GPS or other communication device into your backpack. Also do not forget to tell the mountain police about your summit plans.
Now follwos and overview of the different segments of the hike.
From Nido de Condores to Colera
This is a pretty steep path for which you will need about 2 hours. Esspecially the last meters are pretty steep and you can make a short detour to Berlin to have a smoother ascent. Thats also helpful to gain some bod temperature on the part between Berlin and Colera that is pretty flat and you can therefore walk faster. Also there is another route through Berlin that joins the normal way above Colera which is a little bit shorter but hard to find, especially during the night.
From Colera to Independencia
After reaching Colera you will probably be more exposed to the wind. Also you start feeling the impact of the altitude way stronger, resulting in a reduced walking speed. The path above Colera is pretty smooth until you reach to steeper path just below Independencia. Independencia is another wooden shelter that you will pass by on the normal route. Directly above the shelter is another steep part where you have snow fields to cross at the beginning of the season.
From Independencia to La Cueva
After Independencia you will reach to the Traversia, an exposed path that you can already see from Nido de Condores, where you have to expect strongest winds — definetly cover your face well. You pass a small rock formation called los dedos. When I was there I had to cross another snow field. You can consider putting crampons here — I heard of people falling in the Traversia and sliding down the slope, ending up deadly. This is unlikely but you need to be careful. Finally there is another steep path at the end of the traversia that is already very exhausting for the altitude. At the end of the Traversia you reach La Cueva, a protected place right at the beginning of the Canaleta. Here you can put Crampons if needed and make rest for the final ascent of the Canaleta. Be aware that this final part can take two hours and more.
Canaleta to the summit
The Canaleta can be with ice and you have to be careful for rocks coming down from previous climbers. Therefore it is advisable to put a helmet if there are a lot of other climbers before you. This last part is steep and extremely exhausting. At the end you have another traverse to the summit and then climb it from behind. The summit itself is a large plateau. Enjoy it.
The way down
The way down is easier than up. Try not to wear the crampons for too much time as they force you to walk very unnatural. If you have enough force left you can take a short cut from the middle of the Traversia to Nidos de Condores, going down a straight through the large boulder field. If you started in Colera this is obviously not adviseable. At the Base Camp, do not forget to deposit your trash and get your permit signed for it. The Mules usually leave at about 10 to 11 in the morning — so organise your luggage early enough and listo — you can finally leave the park and hopefully enjoy some days in Mendoza with a lot of wine and good argentinia food.
Good Luck!
Equipment List
- High mountain tent
- Backpack (80L) + Cover
- Duffl Bag (for Food etc. on Mule Transport)
- Sleeping Bag (min. -20°C)
- Camping Mattress
- Trecking Poles
- Crampons
- Gaiters
- Helmet
- Thermos Bottle
- Emergency Biwi — two persons
- Hand Warmers
- Hiking boots
- Double boots
Clothing
- Thick Down Jacket (-30°C)
- Water Proof Shell/ Jacket
- Down gloves
- Linen Gloves
- Waterproof trousers
- Down trousers
- Ski Goggles
- Face Cover
- Thermo Underwear (multiple layers)
- Mid layer Clothings
- Thin Down Jacket
- Trekking socks
- Heavy mountaineering socks
- Hiking trousers
- Buff and Hat
- Sunhat
- Balaclava
Camping:
- Gas cooker
- Gas stove (about twolarge stoves for two weeks)
- Pot
- Solar Charger and power bank
- Bowl, mug, knife, fork, spoon
- Hand desinfectant
- Toilet Paper for the high camps
Other things:
- Sunscreen
- Diarrhoea medication
- Antibiotics
- Ibuprofen
- Altitude medication
- Antiseptic cream
- Electrolytes
- … other first aid medicine
- Water purification