Though over 90 percent of the waterfalls in Washington State are located west of the Columbia River, the arid landscapes of the eastern half of the state hold a few surprises. This region consists of all land east of Highway 97, bound on the remaining sides by British Columbia, Idaho and Oregon.
While rolling mountains are common on the north and east sides of the Columbia River, the primary feature of the flat central portion of Washington is the Channeled Scablands. Formed when an ice dam holding back Glacial Lake Missoula burst, the resulting floodwaters surged across the state, in some places as much as 1000 feet deep, stripping away topsoil and loose rock, forming a huge series of canyons and valleys. Crab Creek, Cow Creek, Rock Creek, as well as the Palouse and Columbia Rivers now occupy some of these canyons. Due to the lack of rainfall in this portion of the state, waterfalls are much less common, but where they do occur, tend to be noteable.