Drumheller Channels National Natural Landmark showcases the Drumheller Channels, which are the most significant example in the Columbia Plateau of basalt butte-and-basin Channeled Scablands. This Nati
Drumheller Channels
Ice Age Floods Institute tour of the Drumheller Channels; note the two people in the foreground and the group in the background that provide perspective in the large-scale erosion here.
Sentinel Gap
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Sentinel Gap is a water gap formed by the Columbia River in the Saddle Mountains, near Mattawa in Washington state. The gap is "a water gap where erosion by the Columbia River was able to keep pace wi
Sentinel Gap