Viedma, Volcanic peak in Southern Patagonia, Chile

Viedma is a supposed subglacial volcano in the Southern Patagonian Ice Field, southwest of Mount FitzRoy. Its candidate edifice, the Viedma Nunatak, rises about 1,500 metres above sea level, but most of it is buried under the Viedma Glacier and only parts crop out. The nunatak is elongated north–south and shows glacial striations and drifts; rock samples are Jurassic metamorphic gneiss and schists, with no magmatic rocks found.

In 1944–1945 and 1950, survey flights reported possible fumaroles at the Viedma Nunatak, which became known as "Volcan Viedma". A 1958–1959 expedition found pumice on the Viedma Glacier but no magmatic rocks in the nunatak, and in April 2019 the Global Volcanism Program removed Viedma from its list of volcanoes.

The name Viedma comes from the nearby Viedma Lake and Glacier, named after the Spanish explorer Francisco de Viedma. The nunatak was long called "Volcán Viedma" after survey flights in 1944-1945 and 1950 reported possible fumaroles. In April 2019 the Global Volcanism Program removed it from its list of volcanoes.

The site is accessible only to specialized mountaineering expeditions due to its position beneath heavy ice and extreme weather conditions. Visitors planning to visit should prepare for rapid weather changes and travel with experienced guides familiar with glacial terrain.

In April 2019 the Global Volcanism Program removed Viedma from its list of volcanoes, after a 1958–1959 expedition found only Jurassic gneiss and schists on the nunatak and no magmatic rocks. The craters reported there were later reinterpreted as glacial cirques holding tarn lakes.