As the name suggests, Dry Falls no longer carries water, but is the remnant of what was once the largest waterfall known to have existed on earth. Viewing the 3.5 miles of sheer cliffs that drop 400 feet, it is easy to imagine the roar of water pouring over them. (Niagara Falls by comparison, is one mile wide with a drop of 165 feet).
The falls were created following the catastrophic collapse of an enormous ice-dam holding back the waters of what has been named "Glacier Lake Missoula". Water covering three thousand square miles of northwest Montana, about the volume of Lake Ontario, was locked behind this glacial dam until the rising lake penetrated, lifted and then blew out the ice dam. The massive torrent (known as the Missoula Flood) ran wild through the Idaho panhandle, the Spokane River Valley, much of eastern Washington and into Oregon, flooding the area that is now the city of Portland under 400 feet of water.
Reaching the Dry Falls area, this tremendous force swept away earth and rock from a precipice actually 15 miles south of the falls near Soap Lake, causing the falls to retreat to its present position, now known as Dry Falls. The falls is said to be a spectacular example of "headward erosion". If this is confusing, given the present topography, it also helps to know the falls are on an ancient course of the Columbia River. The river had been diverted this way by the encroaching glaciers. It returned to its present course as the ice retreated.
The landscape we see today is one with hundreds of small lakes, flat-top mountains, and canyons known as "coulees" (ravines and ancient basins of waterfalls, some still holding water). All have been left several hundred feet above the present course of the Columbia River. Grand Coulee Canyon, at 50 miles in length, and 1 to 5 miles across, is the largest of the channels gouged by a deluge.
The raw material so ferociously sculpted by the floodwaters is basalt. It is actually a black rock, yet you are presented with a landscape of rusty browns, as a result of the iron oxidizing in the exposed rock. In places the browns are highlighted by yellow lichen. The geometrical basalt shapes, in the form of blocks and pinnacles and columns were exposed but not carved by the flood waters. Rather, they formed as basalt lava cooled into rock.
Prior to the floods, between about 17- and 6 million years ago, the basalt was laid down in successive lava flows that engulfed parts of Washington, Oregon and Idaho, gradually filling valleys and covering hills. In places it became more than two miles thick. Some even streamed all the way to the Pacific Ocean. Nature certainly wasn't restrained in this region! The lava field became the second biggest in the world, covering over one hundred thousand square miles, and is now known as the Columbia Plateau. The "high desert" plateau with its exposed lava formations dominates central, inland Pacific Northwest.
The falls are located 7 miles southwest of Coulee City in northeast Washington. It is a feature of Grand Coulee Canyon, which is itself part of the Channeled Scablands that cover three-quarters of eastern Washington.
Washington Home Page |
Washington Aquariums |
Washington Beaches |
Washington Bed and Breakfasts Inns |
Washington Campgrounds |
Washington Cemeteries |
Copyright A View of America 1998 all rights reserved any and all content on this site is protected by law. Any use with out written permission is strictly prohibited.