Aconcagua Medical Guide: Altitude Illness, Viento Blanco & Emergency Resources
At 6,961m — the highest peak outside Asia — Aconcagua demands serious altitude medicine without the safety net of supplemental oxygen. Extreme UV, violent storms, and a high documented HAPE rate make pre-climb preparation non-negotiable. Written by a Registered Nurse.
Medical Disclaimer. This page is written by a Registered Nurse and is intended for general informational and educational purposes only. It does not constitute professional medical advice, diagnosis, or treatment, and is not a substitute for guidance from a licensed physician or qualified wilderness medicine provider. Always consult your doctor before any high-altitude expedition and discuss personal risk factors, medications, and emergency protocols. In a life-threatening emergency in Argentina, call 107 (SAME medical emergency) or 911. Global Summit Guide and its contributors assume no liability for decisions made based on the information on this page. Last reviewed: April 2026.
Aconcagua is the highest mountain in the Western and Southern hemispheres, and the highest peak in the world outside Asia. At 6,961m (22,838 ft), it sits comfortably above the altitude threshold where HACE and HAPE become serious risks — yet unlike Everest or the 8,000m peaks, the vast majority of climbers attempt it without supplemental oxygen. This makes acclimatisation not a protocol to follow, but a physiological necessity that determines whether your body can function at all in the upper camps. Add Aconcagua's notorious Viento Blanco (white wind) storms that can pin teams at high camp for days, extreme Andean UV radiation, and a remote location where helicopter extraction is weather-dependent, and you have a mountain that demands the same medical preparation as peaks twice its size.
Aconcagua's Three Medical Risk Zones
Aconcagua's Normal Route from Plaza de Mulas gains over 2,600m from base camp to summit — all of it above 4,300m, all of it without supplemental oxygen as standard. Each zone presents a distinct clinical picture.
Unlike Everest, supplemental oxygen is not standard practice on Aconcagua. This means your body must genuinely adapt to functioning at nearly 7,000m. The standard acclimatisation protocol involves multiple rotations — going high and sleeping low — over 15–20 days. Climbers who compress this schedule to save time or catch a weather window consistently show higher rates of AMS, HACE, and HAPE. Your acclimatisation schedule is not a training plan; it is a medical protocol.
Altitude Illness: AMS, HACE & HAPE
Aconcagua has one of the highest documented HAPE rates of any major peak — some studies cite incidence of 1–3% of all climbers, significantly higher than many comparable peaks. The combination of rapid ascent profiles, high motivation to summit, and no supplemental oxygen creates the conditions HAPE needs. The Lake Louise Score is the standard field assessment tool at every camp. Use it.
Acetazolamide 125–250 mg twice daily, starting 24 hours before significant ascent, is the best-studied prevention medication for AMS. It is prescription-only. Side effects — increased urination and finger tingling — are expected and harmless. Do not take if allergic to sulfonamides. At Aconcagua's elevations, many expedition doctors recommend Diamox from Base Camp onward for those with any history of AMS. Ibuprofen 600 mg three times daily also shows AMS prevention benefit. Note: Diamox increases urination — compensate with extra fluids.
Acute Mountain Sickness (AMS)
AMS is nearly universal during the first days at Plaza de Mulas (4,300m) and very common during any upward movement above Camp 1. On Aconcagua, where teams spend multiple nights at each camp, there is time to rest and acclimatise — use it. Never push upward with an active headache. The mountain will still be there tomorrow.
High Altitude Cerebral Edema (HACE)
HACE at Aconcagua's high camps (above 5,500m) is a serious emergency made more dangerous by the fact that weather and distance may delay evacuation significantly. The heel-to-toe (tandem gait) test must be performed by companions — a hypoxic climber cannot reliably self-assess. At Nido de Cóndores or above, any ataxia means immediate descent regardless of time, weather forecast, or proximity to summit.
High Altitude Pulmonary Edema (HAPE)
HAPE is the most dangerous altitude illness on Aconcagua and occurs at a higher rate here than on many comparable peaks. The critical early signs — a climber who is quietly falling behind, developing a new cough, or seeming unusually breathless at rest — are easy to dismiss as normal high-altitude fatigue. They are not. HAPE can progress from early warning signs to a life-threatening state within hours at this elevation without supplemental oxygen. Every climbing team member must know these signs and be empowered to raise the concern without social pressure to stay quiet.
Never ascend with AMS symptoms. HACE or HAPE means immediate descent regardless of time, weather, or summit proximity. On Aconcagua, where helicopter access is weather-dependent and medical facilities are in Mendoza (180km away), early recognition and early descent are the only reliable treatment. A turnaround at Camp 2 is survivable. A HAPE event at the Canaleta in deteriorating weather may not be.
Viento Blanco — Storm Entrapment & Hypothermia
Viento Blanco (“white wind”) is Aconcagua's defining weather hazard: violent storms generating sustained winds exceeding 100 km/h (62 mph) with near-zero visibility. They develop rapidly from apparently clear conditions, typically from the northwest, and can pin teams at high camp for 2–5 days. During a Viento Blanco event, the effective wind chill at Nido de Cóndores or the Canaleta can reach −50°C (−58°F). Extended storm entrapment at high camp without adequate shelter, food, or hydration is a compounding medical emergency.
Storm Entrapment & Hypothermia
Frostbite & Extreme Cold Injury
Wind chill during a Viento Blanco event or on a typical summit-day push through the Canaleta can reach −40°C to −50°C (−40°F to −58°F). Fingers, toes, nose, ears, and cheeks are at genuine deep frostbite risk on summit day. The long summit day (10–14 hours) means prolonged cold exposure far beyond what most climbers have experienced on lower peaks. Buddy-check faces and ask companions to report finger and toe sensation at every rest stop — you cannot feel your own frostbite.
Frostbite & Frostnip
Extreme UV & Sunburn
Aconcagua sits at 32° South latitude under the thinner Andean atmosphere, with snow and glacial ice reflecting up to 80% of UV radiation upward. UV index at the summit is extreme — significantly higher than equivalent European or North American altitudes. Severe sunburn develops in under 30 minutes of unprotected exposure on clear days above Base Camp. This is not a comfort issue; severe sunburn at altitude causes fluid shifts, systemic inflammation, and genuine dehydration risk that compounds altitude illness.
Apply SPF 50+ sunscreen to all exposed skin before leaving camp, reapply every 90 minutes on summit day regardless of cloud cover (UV penetrates thin overcast). Cover under the chin — snow reflects UV upward. Protect lips with SPF 30+ lip balm. Wear category 4 glacier glasses with full side shields at all times above Plaza de Mulas. Even partial cloud cover at altitude provides very limited UV protection — do not use it as an excuse to skip sunscreen reapplication.
The Andean dry air at altitude causes significant insensible fluid loss through breathing — far more than at sea level. Your minimum daily fluid target is 4–5 litres at Base Camp and above, including electrolyte-supplemented drinks to replace sodium lost in sweat. Don't wait for thirst; at altitude the thirst response is suppressed and arrives late. Mild dehydration at Aconcagua's elevations accelerates altitude illness symptoms, impairs judgement, and increases frostbite risk through reduced peripheral circulation.
Penitentes & Terrain Injury
Penitentes are sharp, blade-like ice formations — ranging from centimetres to several metres tall — that develop on Aconcagua's glaciated and snow-covered terrain from differential solar ablation. They create uneven, unstable footing that significantly increases ankle sprain and fall risk, particularly on the descent when climbers are fatigued and less careful. The Normal Route's Canaleta (the final steep scree and ice section to the summit) is particularly hazardous on descent — loose, shifting footing combined with exhaustion and hypoxia is the combination that causes most Aconcagua fall injuries.
Falls, Ankle Injury & Terrain Hazards
International Health: Argentina
Argentina is a middle-income country with a well-developed healthcare system and a significantly lower disease burden than tropical climbing destinations. For an Aconcagua expedition, the primary health preparation is altitude-focused. The international health section is deliberately brief — the medical risks are on the mountain, not in Argentina.
Mendoza has modern hospitals with full emergency services capable of managing altitude illness, frostbite, and trauma. Hospital Central de Mendoza has experience with Aconcagua casualties. Medical care quality in Argentine cities is generally good by regional standards. Language is the main barrier — Spanish is universal; English is limited outside tourist areas. Your expedition operator or hotel can assist with translation. Travel insurance for medical treatment and evacuation is still essential.
Vaccines for Argentina
| Vaccine | Status | Notes |
|---|---|---|
| Routine vaccinations | Verify up to date | MMR, Tdap, varicella, annual influenza, COVID-19. No vaccines are required for entry to Argentina. Confirm all routine vaccinations are current before any international travel. Influenza vaccination is especially relevant — a respiratory illness before the climb can abort the expedition. |
| Hepatitis A | Recommended | Standard recommendation for international travel including Argentina. Risk is low in Mendoza and at the mountain, but vaccination is a sensible precaution for any overseas trip. Two-dose series provides long-term protection. |
| Hepatitis B | Recommended | Relevant if you might receive medical care in Argentina. Very commonly administered in childhood in many countries — check your vaccination records. |
| Typhoid | Recommended | Risk is low in Mendoza and urban Argentina, but recommended for travel to any Latin American country, particularly if eating at local restaurants or markets. Injectable or oral vaccine available. |
| Yellow Fever | Only if visiting northeastern Argentina | Yellow fever vaccination is recommended only for travel to northeastern Argentina (Misiones, Formosa, Chaco, Corrientes) — not for Mendoza or Aconcagua. If your itinerary includes these regions, discuss with your travel clinic. Argentina does not require yellow fever proof for entry. |
| Rabies | Low priority for standard Aconcagua itinerary | Rabies is present in Argentina but risk for an Aconcagua expedition focused on Mendoza and the mountain is low. Pre-exposure vaccination is recommended only if you plan extended rural travel or animal contact beyond the standard expedition. Stray dog contact in Mendoza should still be avoided. |
Tap water in Mendoza is generally safe by regional standards, though many travellers prefer bottled water as a precaution. Food safety is significantly better than in most tropical destinations. Traveller's diarrhea occurs but at much lower rates than Nepal or Tanzania. At Plaza de Mulas and high camps, all water comes from meltwater sources and must be treated.
No malaria risk in Mendoza or at Aconcagua elevations. Dengue fever is present in some northern Argentine provinces but not relevant for a Mendoza-based expedition. Above the snowline, insect exposure is negligible. Standard insect repellent is not needed for this expedition.
Hantavirus Pulmonary Syndrome (HPS) is endemic in parts of Argentina and is a genuine, if low-probability, risk for outdoor travellers in the Andean foothills region. It is transmitted through contact with infected rodent urine, droppings, or nesting material — most commonly when disturbing rodent habitats in rural shelters, barns, or camping areas. There is no vaccine. The Aconcagua base camp area has had occasional historical hantavirus cases associated with refugio shelters along the approach route. Do not shelter in enclosed spaces with evidence of rodent activity. Ventilate shelters before use, do not sweep dry rodent droppings (use damp cloth), and store food in sealed containers. Symptoms appear 2–5 weeks after exposure: fever, muscle aches, and rapidly progressive shortness of breath. Any severe respiratory illness within 6 weeks of returning from Argentina requires urgent medical evaluation with hantavirus mentioned to your doctor.
What to Pack: Your Aconcagua Medical Kit
Aconcagua's Base Camp medical post at Plaza de Mulas carries basic emergency supplies and has a physician or paramedic on-site during the main season. Above Base Camp there is nothing. Your personal kit must cover altitude illness emergencies, cold injury management, storm entrapment, and trauma from terrain falls — for the full summit day and any storm-extended stay at high camp.
Prescription Altitude Medications
Environmental Protection
Blister, Fall & Injury Care
Hydration & GI Support
Field Assessment & Communication
Extended High Camp Supplies
Cell coverage at Plaza de Mulas is limited and absent at higher camps. A Garmin inReach or equivalent satellite communicator allows two-way messaging and SOS activation from anywhere on the mountain. Park rangers at the Horcones entrance and Base Camp medical post should be pre-registered as emergency contacts. The Aconcagua Provincial Park rescue service coordinates helicopter evacuation (weather-permitting) — ensure your rescue insurance explicitly covers helicopter evacuation from Argentine territory up to 7,000m altitude.
Nearest Medical Facilities
Plaza de Mulas Base Camp has a staffed medical post (Médico de Base) during the main climbing season (November–March) with a physician or paramedic on-site. Above Base Camp there is no medical facility. Helicopter evacuation from the mountain to Mendoza is weather-dependent and can take 1–3 hours in favourable conditions. All significant cases are transported to Mendoza, approximately 180km from the Horcones trailhead.
Aconcagua Provincial Park rangers coordinate mountain rescue operations. Contact them directly or through your guide team. Argentina's SAME (Sistema de Atención Médica de Emergencias) is the national ambulance system — dial 107. For satellite SOS, GEOS (Garmin's coordination service) will contact Argentine rescue authorities. Weather must permit helicopter access for evacuation above Base Camp; in Viento Blanco conditions, ground evacuation may be required.
| Facility | Location | From Trailhead | Level / Services | Phone |
|---|---|---|---|---|
| Plaza de Mulas Medical Post | Base Camp, 4,300m, Aconcagua NP | On-mountain (seasonal) | Physician or paramedic on-site · Basic emergency care · O₂ · Gamow bag · Helicopter coordination | Via park rangers or guide team |
| Hospital Central de Mendoza | Av. José Vicente Lépez y Planes 2020, Mendoza | ~180 km / helicopter ~1–2h | Primary receiving hospital for Aconcagua casualties · Full ER · Surgical · ICU · Altitude illness experienced | +54 261 420-0600 |
| Clínica Francesa de Mendoza | Av. Boulogne Sur Mer 1558, Mendoza | ~180 km | Private hospital · Good surgical capability · Used by some expedition operators for insured international climbers | +54 261 413-4400 |
| Hospital Húsares de Junin (Uspallata) | Uspallata, Mendoza Province | ~80 km from trailhead | Small district hospital · Basic stabilisation only · Transfer to Mendoza required for serious cases | +54 261 490-0023 |
| Aconcagua Provincial Park Office | Horcones Entrance, Mendoza Province | Trailhead | Rescue coordination · Ranger-assisted evacuation · Basic first aid | +54 261 413-5090 |
The Summit Is Optional. Getting Down Is Not.
Aconcagua's summit rate for those who complete full acclimatisation protocols is high. The summit rate for those who rush, ignore AMS, or push through early HAPE symptoms is far lower — and those who don't summit often don't come down well. The medical knowledge on this page matters most in two moments: when you're deciding whether to push upward with a headache, and when a teammate is falling behind and you're deciding whether to raise the concern. In both cases, the right answer is the conservative one. Aconcagua will be there next season.