Geography of South America
South America consists of three physical and climatic regions:
1 The coast
2 The Andes
3 The tropical eastern flanks of the Andes and the upper Amazon basin.
The coastal plains are very narrow. The northern part (in Ecuador, north of Guayaquil) has a hot tropical climate with a wet summer season (January - April), but the sea is cold. The Humboldt current brings cold water from the far south of the Pacific (from the Antarctic) up the South American coast, so although there are good beaches along the whole length of the continent's west coast, international beach resorts are absent. Some parts of the coast also suffer from fog (e.g. at Lima) due to the warm air passing over the cold water (this situation parallels that of the Californian coast). In places the sea is very polluted. The coastal plains from Guayaquil southwards are deserts, though they are very fertile when irrigated.The Sierra
The coastal plains quickly rise to the mountains of the High Andes. In Ecuador and Bolivia the mountain ranges are divided by a high valley or dry plateau (known as the Altiplano in Bolivia) where most of the Indian population lives (the average height is 3 - 4000 m). The peaks of the Andes rise to over 6000 m (e.g. Huascaran at 6768 m). Some, for example Cotopaxi (5896 m), are active volcanoes. The scenery is spectacular with glaciers and snowcapped peaks. The climate obviously becomes colder with altitude: at 2-3000 m the temperature can drop to near freezing at night but rises to just over 20° C in the day. However, the climate is quite dry so the mountains provide good conditions for trekking. The lack of oxygen in the thin air can bring on breathlessness and heart pounding, but some visitors may also suffer from the symptoms of mountain sickness (headache, dizziness, nausea etc.) until they acclimatize (over a period of about a week).The eastern flanks of the Andes and the Amazon Basin
These areas are open to rainbearing winds and have heavy rainfall in the Southern Hemisphere summer (Nov-May). Temperatures rise as the Andes fall away towards the equatorial lowlands of the Amazon Basin. The transitional foothills (at altitudes between 600-1600 m) are known as the Oriente in Ecuador, the Montana in Peru, and Llanos in Bolivia. The natural vegetation is tropical or subtropical forest, and these regions are sparsely populated and mostly underdeveloped. The territory of each of the three countries extends far enough east to reach the genuine equatorial rainforest of the low-lying Amazon Basin with its high temperatures and year-round rainfall. The most extensive area is in Peru, in the region known as the Selza. The three countries thus have much in common in terms of their cultural background and their physical characteristics. Their pattern of tourist development show similarities but there are some differences in each country's policy and approach.