Introduction to wind-eroded valleys: Wind-eroded valleys and wind-eroded residual hills are common in the southern part of the park. Wind-eroded valleys are caused by heavy rains eroding the surface into many ravines, and then winds blow erosion along these ravines. In this way, heavy rain and wind repeat many times. Due to erosion, the valley gradually widens and deepens, developing into a canyon, which is called a wind-eroded valley.