Sentinel Gap Looking South from Frenchman’s Spring Coulee
This image was taken from the bottom of Frenchman’s Spring Coulee near where it enters the Columbia River. Sentinel Gap was cut across the Saddle Mountains by the Columbia River and the Ice Age Floods. During the floods, the Columbia River was at a level near the top of the eastern slope of the Gap. On the north side of the Gap, the Vantage Bridge and Wanapum Dam are faintly visible. Through the Gap, Umatilla and Rattlesnake Ridges are visible. And of course, the clouds make the image.
Sentinel Gap, Washington
This image was taken looking north through Sentinel Gap. This gap cuts through the Saddle Mountains which separate the Pasco and Othello basins in Eastern Washington. The Columbia River runs through this gap on its way to the Oregon/Washington border. At the time of the Missoula Floods, the water level going through the gap reached the top of the left ridge, flowing into Lake Lewis which covered the Pasco basin.
The erratics in the foreground most likely are from the gap, carved away by the raging wall of water that flowed through it.