In the heart of the Chilean mountain range, where the weather does not forgive and the terrain commands respect, more than 600 mountain soldiers from Argentina, Chile, the United States, and Peru faced more than just snow, wind, and cold. They tested their ability to operate as a single multinational force, cohesive and prepared to respond in real crisis scenarios. This was the experience of Southern Vanguard 2025, the main combined mountain combat exercise of the Southern Hemisphere.
For twenty days —between August 11 and 29—, the troops deployed in the Biobío Region turned the inhospitable environment of Antuco into an international operations center, where tactics, logistics, and the human factor were just as challenging as the icy slopes and cutting winds. But this exercise was not just a practice: it was a realistic rehearsal of tactical integration and regional cooperation, led by the Chilean Army’s III Mountain Division, within the framework of bilateral agreements with U.S. Army South.
The participating units included the 10th Mountain Division of the U.S. Army, a contingent of the “Cazadores 6” Company of the Argentine Army’s VI Mountain Brigade, and a specialized squad from the Peruvian Army’s Mountain School. All united under a common objective: strengthening interoperability in extreme environments and improving preparedness for winter combat scenarios.
A political and strategic signal
Southern Vanguard, in its second edition, transcends what is strictly military. Its message is clear: hemispheric cooperation is no longer a speech, it is an operational reality. The presence of the U.S. Army alongside South American forces with proven experience in difficult terrain reflects a concrete commitment to regional stability and preparedness for multinational crises.
For three weeks, the soldiers carried out a series of maneuvers that included mountain living, ski movements, night patrols, simulated combat, rescue under fire, and medical evacuation, all in real and demanding weather conditions. Each day was a test of physical adaptation, technical expertise, and above all, multinational tactical coordination.
One of the keys to success was the initial doctrinal leveling phase, led by Chilean instructors. This stage not only adjusted techniques and procedures, but also aligned command criteria, communication, and tactical execution, eliminating frictions between forces with different doctrines and operational cultures.
Interoperability is not only built with rifles and radios. It is also waged in supply lines, in the transportation of equipment, in the support of deployed units. Southern Vanguard 2025 was, in many ways, a high-complexity logistical operation, where more than 600 troops were sustained for almost a month in extreme conditions, including altitude, deep snow, and sub-zero temperatures.
From the habitability of the camps to the supply of fuel, food, ammunition, and medical evacuation, every detail was planned with precision. Brigadier General Claudio Mardones, Commander of the III Mountain Division and director of the exercise, summarized it as follows: “Achieving this interoperability was not a coincidence. It involved months of planning and meticulous execution. The logistical and administrative deployment was fundamental for each operation to happen.”
Beyond tactical maneuvers, Southern Vanguard demonstrated something fundamental: real interoperability is not imposed, it is built. And it is built on the human level: in sharing rations under the snow, in night marches with zero visibility, in multilingual coordination that requires patience and leadership, and in the trust forged among soldiers who had never seen each other before, but who learn to operate as one.
Major General Philip J. Ryan, Commander of U.S. Army South, was categorical: “This exercise is a demonstration of our real collaboration. It is not just about geopolitics, it is about the soldiers working side by side. In difficult terrain, with cold and fatigue, we demonstrated that together we are stronger.”
Toward an integrated hemispheric force
Southern Vanguard 2025 left several lessons, but one of them stands out: regional integration in defense is possible, tangible, and necessary. Faced with an increasingly complex strategic scenario, with hybrid threats, climate crises, and geopolitical challenges, the only effective response is a force capable of operating jointly, flexibly, and professionally.
Chile, by assuming operational and doctrinal leadership of the exercise, consolidates its role as a continental reference in mountain operations, while the United States reaffirms its commitment to reliable and lasting partnerships in the southern part of the continent. Argentina and Peru, for their part, contributed not only presence but also concrete experience in adverse geography.
Southern Vanguard is not a postcard of winter training. It is a demonstration of tactical and strategic cohesion in the Southern Hemisphere. Because when nations share not only terrain but also vision and values, what is built goes beyond interoperability: it is mutual military trust to face tomorrow’s challenges together.
*Photographs: Chilean Army
*Original text written in Spanish by Rodolfo Neira Gachelin
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