According to Luis Lliboutry the Dry Andes can be defined by the distribution of penitentes.

[2] The Principal Cordillera near Santiago may have been subject to significant glaciation as early as 1 million years ago, as indicated by the development of glacial valleys.

[3] Though precipitation increases with the height, there are semiarid conditions in the nearly 7,000 metres (23,000 ft) towering mountains of the Andes.

This dry steppe climate is considered to be of the subtropic type at 32-34° S. In the valley bottoms only dwarf shrubs grow.

Its dendritic glacier arms, i.e. components of valley glaciers, were up to 112.5 kilometres (69.9 mi) long, over 1,250 metres (4,100 ft) thick and spanned a vertical distance of 5,150 metres (16,900 ft).