Glaciers release a great deal of water as they melt, usually in streams that exit from the snout carrying large quantities of fresh-ground rock. Where the ground is relatively flat, the sediment builds up in an outwash plain and the meltwater streams wander over it in a braided pattern, helpless to dig into the sedimentary abundance. This outwash plain is at the terminus of Peyto Glacier in Banff National Park, Canada.
Another name for an outwash plain is sandur, from the Icelandic. The sandurs of Iceland can be quite large.