Grand Coulee, Washington
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Rose Red
N 47° 58.277 W 118° 59.150
11T E 351786 N 5315016
The diverted Columbia River eroded much of the Grand Coulee, and the part of the Spokane [Missoula Ice Age] floods that came this way did the rest of the job.
Waymark Code: WM4EW8
Location: Washington, United States
Date Posted: 08/14/2008
Views: 53
According to “Roadside Geology of Washington” by Alt and Hyndman, the Grand Coulee, north and south of Coulee City, is one of Washington’s geologic spectaculars. During the last ice age, a glacier blocked the Columbia River about 50 miles north of this area to impound Glacial Lake Columbia, which drained through the Grand Coulee. The Columbia River was much bigger than it is now. So the diverted river eroded much of the Grand Coulee, and the part of the Spokane [Missoula Ice Age] floods that came this way did the rest of the job. When the glacier melted, the Columbia River returned to its old [original] channel, and left the old [Grand Coulee] stream channel and floodway without a flowing stream. U.S. 2 crosses Grand Coulee at the dividing point between upper and lower Grand Coulee. Dry Falls, about 3 miles southwest of Coulee City, is located at the head of lower Grand Coulee. The coordinates were taken near a concrete observation platform high above Grand Coulee Dam.
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