Waterfalls are commonly formed in the upper course of a river where lakes flow into valleys in steep mountains.[10]

A river sometimes flows over a large step in the rocks that may have been formed by a fault line. Waterfalls can occur along the edge of a glacial trough, where a stream or river flowing into a glacier continues to flow into a valley after the glacier has receded or melted. The large waterfalls in Yosemite Valley are examples of this phenomenon, which is referred to as a hanging valley. Another reason hanging valleys may form is where two rivers join and one is flowing faster than the other.[10]

When warm and cold water meet by a gorge in the ocean, large underwater waterfalls can form as the cold water rushes to the bottom.[11]

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canon 6d mark ii