A visit to Monte Tronadór requires an all-day outing, covering 170 km (105 miles) round-trip from Bariloche. This 3,658-meter (12,000-foot) extinct volcano—the highest mountain in the northern Lake District—straddles the frontier with Chile, with one peak on either side. Take R258 south along the shores of Lago Gutiérrez and Lago Mascardi. Between the two lakes the road crosses from the Atlantic to the Pacific watershed. At Km 35, turn off onto a road marked "Tronadór" and "Pampa Linda" and continue along the shore of Lago Mascardi, passing a village of the same name. Just beyond the village the road forks, and you continue on a gravel road, R254. Near the bridge the road branches left to Lago Hess and Cascada Los Alerces—a detour you might want to take on your way out.
As you bear right after crossing Los Rápidos Bridge, the road narrows: note that it’s one-way heading up from 10:30 am–2 pm, one-way heading down from 4 pm–7:30 pm, and two-way from 7:30 pm–10:30
am only. The lake ends in a narrow arm (Brazo Tronadór) at the Hotel Tronadór, which has a dock for tours arriving by boat. The road then follows the Río Manso to Pampa Linda, which has a lodge, restaurant, park ranger's office, campsites, and the trailhead for the climb up to the Refugio Otto Meiling at the snow line. Guided horseback rides are organized at the lodge. The road ends 7 km (4½ miles) beyond Pampa Linda in a parking lot that was once at the tip of the receding Glaciar Negro (Black Glacier). As the glacier flows down from the mountain, the dirt and black sediment of its lateral moraines are ground up and cover the ice. At first glance it's hard to imagine the tons of ice that lie beneath its black cap.