<P> Although the almost total lack of precipitation is the most prominent characteristic of the Atacama Desert, exceptions may occur . In July 2011, an extreme Antarctic cold front broke through the rain shadow, bringing 80 cm (31 in) of snow to the plateau, stranding residents across the region, particularly in Bolivia, where many drivers became stuck in snow drifts and emergency crews became overtaxed with a large number of rescue calls . </P> <P> In 2012, the altiplano winter brought floods to San Pedro de Atacama . </P> <P> On 25 March 2015, heavy rainfall affected the southern part of the Atacama Desert . Resulting floods triggered mudflows that affected the cities of Copiapo, Tierra Amarilla, Chanaral, and Diego de Almagro, causing the deaths of more than 100 people . </P> <P> The Atacama Desert is commonly known as the driest nonpolar place in the world, especially the surroundings of the abandoned Yungay town (in Antofagasta Region, Chile). The average rainfall is about 15 mm (0.6 in) per year, although some locations, such as Arica and Iquique, receive 1 to 3 mm (0.04 to 0.12 in) in a year . Moreover, some weather stations in the Atacama have never received rain . Periods up to four years have been registered with no rainfall in the central sector, delimited by the cities of Antofagasta, Calama, and Copiapó, in Chile . Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971 . </P>

When did it last rain in the atacama desert