Braided Channel of the Salmon River
Near Hyder, Alaska
The Salmon River rushes out of the Coast Mountains on the border between British Columbia and southernmost Alaska. Like many rivers running down from glaciers, its bed is encumbered with huge quantities of stones and gravel, far more than the river can easily carry down to the sea. The river channel, blocked in every direction by all the debris, breaks into multiple shifting channels, that rejoin, then split again, in a pattern known as a braided channel.
There is more to the story here on the Salmon River, though. The glacier at the top of the canyon blocks a side valley, impounding a lake. Periodically this lake either overflows, or finds its way under the glacial ice, then empties suddenly in a catastrophic flood. This is known as a jokulhlaup (an Icelandic word, pronounced YO-kul-ope). The Salmon Glacier has seen many of these sudden floods, almost one a year since 1961.