A US member developed severe HAPE at Base Camp 3 Guanacos on Aconcagua, Argentina. Initial symptoms included persistent headaches, worsening fatigue, cough, and dangerously low oxygen saturation. Due to the critical condition, an emergency helicopter evacuation was arranged. The member was transferred to a hospital in Mendoza, where AMS and HAPE were confirmed. After treatment and observation, the member was discharged with medical advice to take extreme precautions during recovery.