A few minutes further north, a short detour leads to the Desembocadura Lago General Carrera — the point where the outlet of Lago General Carrera narrows and quickens before feeding into the system that eventually becomes the Baker. The bridge here, painted orange, frames a view back across the water. The lake itself, shared with Argentina (where it is called Lago Buenos Aires), is the largest in Chile and the second largest in South America, stretching nearly 200 kilometers in length and reaching depths of around 590 meters (1,935 feet). At the outlet, the lake's extraordinary blue-green — a function of glacial flour suspended in the water — is on full display before the current tightens. The scale of what lies behind that narrow neck of water is worth a moment to absorb.
The road continues north along the lake's western shore, passing through the volcanic landscape left by the 1991 eruption of Volcán Hudson — stands of dead timber, pale and bleached, punctuating the forest roadside — before the Carretera Austral bends south into town.
Arrival: Puerto Río Tranquilo
Puerto Río Tranquilo sits on the western shore of Lago General Carrera and has become the main tourist hub for this section of the Carretera Austral — in high season it is busy, loud by Patagonian standards, and noticeably more expensive than towns further south. The lakefront fills with pop-up tour operator stalls selling morning boat trips to the Capillas de Mármol, the marble formations carved by the lake over thousands of years that are now the region's best-known attraction. The marble caves boat is booked for the following morning; evening is a good time to confirm the slot with the operator, as morning light reaches furthest into the caverns and wind conditions on the lake are typically calmer early in the day. The town has a fuel station, a handful of restaurants, and enough grocery infrastructure to top up before continuing north. Campgrounds fill quickly in high season and prices run higher than elsewhere on the Carretera Austral.