Morning mist in one of the tributaries of the Amazon to Iquitos about 40 miles near the town of Indiana. Seasonal rains give rise to severe flooding along the river and its tributaries. The average depth at the peak of the rainy season is about 40 m and average width is about 40 km (see: Barzee). This starts in November and runs through June, then decreases in late October. The rise of the Black River is partially asynchronous: the rainy season does not start in this valley until February or March. For June is at its peak, and the descent of the water itself now in line with the Amazon. The Madeira River has a gap of two months, beginning to grow in September and starting the withdrawal in abril.La abundance of water in the Amazon system is due to the fact that much of the territory is located in the intertropical convergence zone, where the rainfall is highest. Also, the region is in the area of trade winds of the Atlantic where the moisture is pushed to the west and eventually forced to climb over the Andes. This rising air mass cools, creating heavy rains that are precipitated over a huge area, process mundial.La unparalleled level soft alluvial plain (called Vargem) constituting most of the territory through which flows the river, is covered with up to 15 m of water. The level at Iquitos is 6 m, Teff, 15 m, in Óbidos, Pará 11 m and 4 m above the river level at least that characterizes the dry season.