when the Spanish conquistadors colonized the mountains in the advance of the mining economy. In tide of anti-imperialist nationalism, the Andes became the scene of a series of independence wars in the 19th century when rebel forces swept through the region to overthrow Spanish colonial rule. Since then, many former Spanish territories have become five independent Andean states. Climate and hydrology The climate in the Andes varies greatly depending on latitude, altitude, and proximity to the sea. Temperature, atmospheric pressure and humidity decrease in higher elevations. The southern section is rainy and cool, the central section is dry. The northern Andes are typically rainy and warm, with an average temperature of in Colombia. The climate is known to change drastically in rather short distances. Rainforests exist just kilometres away from the snow-covered peak Cotopaxi. The mountains have a large effect on the temperatures of nearby areas. The snow line depends on the location. It is at between in the tropical Ecuadorian, Colombian, Venezuelan, and northern Peruvian Andes, rising to in the drier mountains of southern Peru south to northern Chile south to about 30°S before descending to on Aconcagua at 32°S, at 40°S, at 50°S, and only in Tierra del Fuego at 55°S; from 50°S, several of the larger glaciers descend to sea level. The Andes of Chile and Argentina can be divided into two climatic and glaciological zones: the Dry Andes and the Wet Andes. Since the Dry Andes extend from the latitudes of Atacama Desert to the area of Maule River, precipitation is more sporadic and there are strong temperature oscillations. The line of equilibrium may shift drastically over short periods of time, leaving a whole glacier in the ablation area or in the accumulation area. In the high Andes of Central Chile and Mendoza Province, rock glaciers are larger and more common than glaciers; this is due to the high exposure to solar radiation. In these regions glaciers occur typically at higher altitudes than rock glaciers. The lowest active rock glacier occur at 900 m a.s.l. in Aconcagua. Though precipitation increases with the height, there are semiarid conditions in the nearly highest mountains of the Andes. This dry steppe climate is considered to be typical of the subtropical position at 32–34° S. The valley bottoms have no woods, just dwarf scrub. The largest glaciers, for example the Plomo glacier and the Horcones glaciers, do not even reach