Calama, Chile Calama, Chile Calama is a city and commune in the Atacama Desert in northern Chile. It is the capital of El Loa Province, part of the Antofagasta Region. Calama is one of the driest cities in the world with average annual precipitation of just . The River Loa, Chile's longest, flows through the city. Calama has a population of 147,886 (2012 census). The commune also encompasses the Quechuas communities of Estación San Pedro, Toconce and Cupo; and the Lickan-antay communities of Taira, Conchi Viejo, Lasana, San Francisco de Chiu Chiu, Aiquina-Turi, and Caspana. In 2003 the nearby town of Chuquicamata,
Flora of the Sonoran Desert absent on the California side of the Colorado River. Desert Holly ("Atriplex hymenelytra") can tolerate even the hottest and driest sites. The area where two vegetation types border, overlap, and transition is called an ecotone. The ecotone between the hotter, drier Colorado Desert and that of the relatively cooler and wetter Arizona Upland occurs from Parker, Arizona southeast to near Phoenix, then south to Organ Pipe Cactus National Monument. Density of vegetation gradually diminishes moving from the Arizona Upland into the Colorado Desert proper. can be found with stems climbing through shrubs and other vegetation, producing "spectacular" floral displays on