The water melting from a glacier plays a very important role in the formation of depositional features at terrestrial glaciers. The majority of sediment eroded by the glacier is carried by the melt streams. The grey color of glacial rivers is a result of a large amount of very fine rock particles, known as glacial flour. At Exit Glacier, the rushing meltwater streams redistribute the sediment deposited in recessional moraines across the outwash plain. The sediment loads carried by the streams create braided stream channels. As the amount of meltwater issuing from a glacier changes, the fluctuating volume of flow determines how much sediment can be carried. When water volume is high, more sediment and larger rocks and boulders move with the flow of the river. As water volume decreases, larger rocks are deposited along the streambed, often blocking or altering the stream channel. Thus, many channels form across a wide, rocky riverbed.