Moses Coulee Coulee, a National Natural Landmark, one of the largest examples of bars created by the Channeled Scablands outburst floods. Moses Coulee cuts into the Waterville Plateau, which lies in the northwest corner of the Columbia River Plateau. The plateau is part of the Columbia River Basalt Group, a large igneous province that lies across parts of the states of Washington, Oregon, and Idaho in the United States of America. During late Miocene and early Pliocene times, one of the largest flood basalts ever to appear on the earth's surface engulfed about 163,700 km² (63,000 mile²) of the Pacific Northwest, forming
Laser light show (Grand Coulee Dam) Laser light show (Grand Coulee Dam) "The laser light show" at Grand Coulee Dam, which began in 1989, is one of the largest light shows in the U.S.. The 37 minute show runs daily from Memorial Day through September 30. An addition of fireworks lights up the sky above the dam each Memorial Weekend Sunday and July 4. The Grand Coulee Dam premiered its first non-laser light show in 1957. Approximately 740 flood lamps near the base of the dam lit up the dam, but not enough water flooded down the spillway for the desired effect. Lasers for the show