Mount Tronador is named for a sound: ice breaking off its eight glaciers with a rumble that runs for kilometres down the valleys. The Thunderer is an extinct volcano on the Argentina–Chile border west of Bariloche. The road in follows the Manso river to Pampa Linda, a meadow at the mountain's foot where every trail starts. Ventisquero Negro, the Black Glacier, is dark as ash because it is buried under rock and grit shed by the glacier hanging above it. It ends in a milky lagoon, with debris-darkened ice hanging over the water. A short forest walk on reaches the Garganta del Diablo, where meltwater pours down a rock amphitheatre in ribbons and the footbridges leave you wet.
After that the walking sorts itself by how close you want to get. Seven kilometres of coihue forest and level valley lead to a lookout facing the Castaño Overa glacier: three hours, three hundred metres of climb, no rope and no crampons. The ice hangs on the wall opposite, shedding waterfalls into the river you crossed on the way, and a serac cracks somewhere above you every so often. The Otto Meiling hut is harder: eleven and a half kilometres and a thousand metres of ascent, four or five hours with a pack, the last of it across open moraine with nothing to shelter behind. It sits around 2,000 metres between two glaciers, and from its terrace cloud sits in the valley with Tronador's ice filling the sky above it. The summit is a multi-day climb, roped to a guide across crevassed glacier platforms and up the final snow to the shared border top. The hut carries the name of Otto Meiling, a German-born carpenter who helped start mountaineering in Bariloche and built it himself in the 1950s. Tronador was his mountain: he went up it more than fifteen times, and once, at seventy-eight, he walked from Pampa Linda to the summit and back in a day.