File:Washington and Oregon (MODIS 2018-05-31).jpg

English: On May 25, 2018, NASA’s Terra satellite passed over the border between Washington and Oregon, allowing the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard to capture a striking true-color image of the area.

The image is centered on the Columbia Plateau in eastern Washington and north-central Oregon, where stretches of earthy tans of rocky cliffs and buttes sweep across green-speckled agricultural land. A number of rivers wind through the complicated geography, including the long and wide Columbia River which flows from the north to the southwest, and the Snake River which rises in the eastern mountains and joins the Columbia near the center of the image.

When viewed from closer to Earth, the tan landforms of the Columbia Plateau can appear somewhat other-worldly, with boulders strewn across the landscape, towering cliffs, and plunging holes appearing suddenly. The austere bedrock wears scars from winding channels. This area, called the “Channeled Scablands” indicates a past that was characterized by violent floods.

To understand origins of the rugged, remarkable terrain of the Channeled Scablands, one must look at the events that took place during the Ice Age which took place 10,000 to 20,000 years ago. A great ice sheet, called the Cordilleran ice sheet, lay across the northern edge of this region. As it slowly ground southward, it formed an ice dam which rose about 2,000 feet (600 meters) high along the Clark Fork River. Behind this dam a giant glacial lake grew. Known as Lake Missoula, it eventually contained as much water as both the modern Lake Ontario and Lake Erie, combined. Eventually the great ice dam broke, suddenly pouring a vast amount of water across the region. It has been estimated that 500 cubic miles of water tore across the region at about 80 miles per hour in the initial rupture. It is believed that the ice dam grew high again, stored more water, and then ruptured … and that this cycle repeated several more times over many years. The repeated flooding carved out spectacular grooves, potholes, and the long channels (“coulees”) that make the geography of this region so unique – and spectacular.