The rain comes suddenly in violent storms, particularly in the late summer of each year. The power of erosion is therefore more evident here than in other places which receive more rain. Grand Canyon owes its distinctive shape to the different rock layers in the canyon walls. The vivid colors of many of these layers are due mainly to small amounts of various minerals. Most contain iron, which imparts subtle shades of red, yellow, and green to the canyon walls.
Climate plays an important role in the appearance of the canyon.
If there was a higher amount of precipitation at Grand Canyon, the plants and trees that grow here would be very different. The canyon walls might be covered with lush vegetation, rather than the cacti and shrubs growing there today. We know that the erosion which has shaped the canyon has occurred only in the past five to six million years. This is only yesterday, considering the age of the rocks through which the river has carved. Grand Canyon continues to grow and change.