Grand Coulee, Washington.
Grand Coulee has walls 400 feet tall and is up to 6 miles wide and was created by the Missoulla floods. The floods topped the cliffs by 300 feet and moved at 65 miles an hour, filling the whole coulee. The fractured basalt was torn out and distributed over 600 square miles downstream.
Dry Falls
Dry Falls, Washington was created by the Missoula floods and receded over 20 miles from where it started. Dry Falls is 3.5 miles wide and 400 feet tall (compared with Niagara at less than a mile wide and 167 feet tall). The flood waters were 300 feet above the top.
