Lomas the lomas owe their existence to the moist dense fog and mist which rolls in from the Pacific. The fog is called garúa in Peru and Camanchaca in Chile. According to the Köppen Climate Classification system, the coastal desert of Peru and the Atacama desert of Chile feature a rare desert climate, that is abbreviated "Bwn" on climate maps with the n denoting frequent fog. Temperatures are mild year round and precipitation is nearly non-existent, averaging to per year in most locations. Many years have no precipitation at all. The Atacama Desert of Chile is commonly known as the driest
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