This photo is from a field trip that a small delegation of us made, out in what’s called The Channeled Scablands, in eastern Washington State.
|Shorelines at Missoula, MT|
During its race to the sea, Lake Missoula tore through western Washington, scouring the land to bed rock. In places where the water was forced to channelize, it left large Coulees*, some cutting nearly a thousand feet into the hard basalt. The aforementioned photo was made in Moses Coulee, which is one of the three largest coulees in the area. The cliff walls on each side are about 600 feet high, standing over a mile across.
|Dry Falls in Lower Grand Coulee|
The place that saw the greatest action of the Missoula Flood, was the Grand Coulee. The Grand Coulee is split in two section; Upper Grand Coulee, and Lower Grand Coulee. During the early stages, both Upper and Lower Grand Coulees boasted some rather impressive receding waterfalls, but today, the only one left is in the Lower Coulee, which has been appropriately named, Dry Falls. Dry Falls is a double horse-shoe receding water fall. About five times the size of Niagara, Day Falls had an estimated flow rate equal to ten time the current flow of all the rivers in the world. It’s estimated that the falls only flowed for 48 to 72 hours.
Large basalt remnant downstream of the Dry Falls.
Dry Falls was a double horse-shoe shape,
and this rennet is at the end of the shoe.
Before making it out to sea, the flood waters backed-up in the Willamette Valley, where they dumped most of the Scablands topsoil. After making its way through the narrows near Kalama, Washington, Glacial Lake Missoula entered the Pacific Ocean, never to be seen again.
|Heading south on State Road 17 through the Lower|
Grand Coulee. Funny to think we were traveling at
roughly the same speed that the Lake Missoula Flood
was when it traversed the same path nearly 3,000 years