Field of Penitentes on the upper Rio Blanco, Central Andes of Argentina. The blades are between 1.5 and 2m in height, slightly tilted northwards, or more exactly about 11°, the approximate position of the sun at noon at this latitude and time of the year.
Photograph of small penitentes taken in the summit crater of Mount Rainier. Photographed here, penitentes are approximately 50cm high tilted southwards towards the sun.
Penitentes ice formations at the southern end of the Chajnantor plain in Chile.
Penitentes, or nieves penitentes, are a snow formation found at high altitudes. They take the form of tall thin blades of hardened snow or ice closely spaced with the blades oriented towards the general direction of the sun. Penitentes can be as tall as a person.
These pinnacles of snow or ice grow over all glaciated and snow covered areas in the Dry Andes above 4,000 m (Lliboutry 1954a, Lliboutry 1954b, Lliboutry 1965). They range in size from a few cm to over five metres. (Lliboutry 1965, Naruse and Leiva 1997).