Desafío Los Alerces

Glacial valleys carved into the Patagonian Andes hold the waters of Lago Futalaufquen, where open water swimmers gather in a remote alpine landscape framed by high mountain peaks. The Desafío Los Alerces is an open water swimming race held in the glacial waters of Lago Futalaufquen, situated within the Parque Nacional Los Alerces near Villa Futalaufquen in the province of Chubut, Argentina. Taking place during the southern summer in February, the event invites distance swimmers to test themselves in a deep freshwater lake shaped by ancient ice. The competition offers four distinct course lengths to accommodate varying levels of experience: a short 500-meter course, a 1,500-meter race, a 3,800-meter distance, and an endurance test of 10,000 meters.

Swimmers can enter either standard wetsuit categories or race in the NAF division without neoprene, adhering to traditional cold-water swimming principles across designated distances. Stepping into the lake without neoprene requires mental focus as the cold mountain water meets the skin, sharpening every breath as you settle into a steady rhythm away from the shore. Swimmers can also participate in team categories, with rankings calculated on the cumulative ages of all squad members at the close of the calendar year.

Lago Futalaufquen: glacial origins and Pacific watershed

Lago Futalaufquen occupies a long, steep-sided glacial basin set within narrow valleys between glaciated Andean peaks. Moving through the water along the shoreline, the mountain massifs rise sharply above the surface, providing bold natural sighting marks against the horizon. The rhythmic pull of strokes takes you across an immense alpine reserve, where open water distance reveals the imposing geological scale of the surrounding valleys. The basin is continuously replenished by the Arrayanes River, which discharges its current into Lago Futalaufquen after collecting mountain waters from Lake Menéndez and Lake Rivadavia upstream. Each stroke in Futalaufquen Lake connects swimmers to an aquatic corridor that cuts entirely through the mountain barrier toward the western ocean.

Monster Narrows and the southern waters toward Lake Krüger

The wide basin tapers into a restricted passage known locally as the Monster Narrows. While the name might evoke fearsome mountain legends, it actually derives from the exceptionally clear water where massive trout can easily be spotted swimming below the surface. The Monster Narrows function as a water gate linking Futalaufquen directly with Lake Krüger, an adjacent body of water that forms the natural continuation of Futalaufquen's southern lobe. Lake Krüger is also a glacial lake lying entirely within Los Alerces National Park, fed by inflows from Lake Stange and Lake Chico. As part of the same transcontinental hydrological network, Lake Krüger empties its waters into Chile via the Yelcho River, bound for the Pacific Ocean.

Glacial lagunas of Los Alerces

Laguna Larga, located within the boundaries of Los Alerces National Park, occupies a basin hollowed out by a glacier that vanished after the last ice age. Sitting at an altitude of 811 meters above sea level, this glacial lake stretches for 3.5 kilometers across the terrain. Like the larger lakes nearby, Laguna Larga belongs to the Futaleufú river basin, eventually discharging its volume into the Pacific Ocean through Chilean territory. The emissary stream of Trafipan emerges from its northeast shore, descending sharply across a 400-meter vertical drop over a course of six kilometers as it journeys toward the Futaleufú river system and the Pacific. Another distinctive glacial water feature within the cordillera is Laguna La Pera, positioned at an altitude of 1,002 meters above sea level.

True to its name, this compact Andean water body features a distinct ovoid, pear-like outline measuring 420 meters in length and 160 meters at its widest point. Fed by mountain streams that trickle down from the slopes of the Cordón Rivadavia, Laguna La Pera drains outward into neighbouring Laguna La Banana, preserving the quiet rhythms of high-altitude glacial hydrology.

The Patagonian forest and Emilio Frey's river

Swimming parallel to these forested banks gives a feeling of profound isolation, where the silence of the national park is broken only by the splash of rhythmic arm recovery and the lap of lake water against the shore. Further south from Lake Krüger, the waters gather into the Frey River, a fast-moving current renowned for turbulent white-water rapids that skirt the western flank of the Situación mountain range. The river honors Emilio Frey, an engineer who survived a perilous shipwreck in its churning rapids during an exploratory expedition in the nineteenth century. Swelled by tributaries such as the Toro Alzadio, the Frey River flows outward into the Amutuy Quimey reservoir, also known as Lake Situación, as part of the broader Futaleufú basin heading toward the Yelcho River in Chile. Away from the turbulent rapids of the southern river exits, the broad waters of Lago Futalaufquen offer open water swimmers a tranquil yet challenging arena framed by pristine Patagonian wilderness.