Twin Sister's Rocks
The first time I learned of these two towering basalt rocks was when I followed the journey of the Corps of Discovery with Lewis and Clark. But oddly enough, The Twin Rocks were never specifically mentioned in their journals, unlike other rock features documented during their journey. 
Clark described the exposed basalt walls at the Wallula Gap as "black rugid rocks ..." [William Clark, October 18, 1805]
Clark described the exposed basalt walls at the Wallula Gap as "black rugid rocks ..." [William Clark, October 18, 1805]
When my own two sisters moved to the Tri-Cities area, I made it a point, when visiting them, to go find these dominant looking natural sculptures along the Columbia River.
The Wallula Gap, a natural water gap of the Columbia River, is one of the most significant and spectacular features created by the great Ice-Age floods. 
Only one other flood feature in the Mid-Columbia Basin, Drumheller Channels, shares this distinction. This choke point is located 15 miles south of Pasco, Washington. Wallula Gap is the only outlet for stream flows for the entire Columbia River Basin of eastern Washington.
This map illustrates the origin of the great ice age floods, Lake Missoula, in Montana. The flood path crosses the scablands of eastern Washington and congregated at the Wallula Gap. From there, the flood waters scowered down the Columbia Gorge backing up again around The Dallas and again near the current Bonneville Dam. Flood waters eventually made it way to current day Portland and backed up into the Willamette Valley. Glacier rocks with an origin in Montana were deposited throughout the Willamette Valley. Eventually the flood water met the Pacific. Gravel from Montana can be found up to three miles out to sea from the mouth of the Columbia River.
Floodwaters from Glacial Lake Missoula spread out over an area almost 100 miles wide across the Channeled Scabland of eastern Washington, so its not difficult to understand why the waters backed up when suddenly forced to pass through an opening as small as two miles wide. 
The Twin Sister's were under 600 feet of water during peak floods. They were definately shaped by the power of erosion.
Sage brush, wild flowers, and blowing sand dominates the uplands of the Wallula Gap.
I took this photo of an old starving Juniper...one of only two trees I could find in the immediate area. The arid climate and lack of vegetation gives a great perspective view of the awesome landscape created by the Ice Age Floods, as seen in the photo below taken by the author of On the Trail of Ice Age Flood, Bruce Bjornstad.
I still have a hard time understanding why Lewis and Clark didn't find these basalt formations worthy of documenting...?
The National park Service did though, and in 1980 The formations within the Wallula Gap were designated as a National Natural Landmark.
The National park Service did though, and in 1980 The formations within the Wallula Gap were designated as a National Natural Landmark.
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During their journey, Lewis and Clark described many things about the people and landscapes they encountered on their expedition. But they also misunderstood and missed many things...
In the upper Columbia region, Lewis and Clark stressed over the lack of firewood. They did not understand why salmon were dying. They bought many dogs for food. And, they noted a rock "resembling a hat" located down river from the Twin Sisters at the southern end of the Wallula Gap. 
In the upper Columbia region, Lewis and Clark stressed over the lack of firewood. They did not understand why salmon were dying. They bought many dogs for food. And, they noted a rock "resembling a hat" located down river from the Twin Sisters at the southern end of the Wallula Gap.
Hat Rock, named by Captain Clark, was the "first" distinctive landmark passed by the Lewis and Clark Expedition on their journey down the Columbia. Hat Rock, located in Oregon, rises 70 feet above the desert sage terrain and is one of the few remaining landmark sites of the Lewis and Clark Expedition not underwater. Clark wrote, "... a rock in a Lard. resembling a hat just below a rapid at the lower Point of an Island in the Midl: of the river ..." [Clark, October 19, 1805].
The flood sculpted basalt rock does indeed resemble a simple looking, hat. Maybe Lewis and Clark skipped over the Twin Sister's in Washington because the feature, to them, didn't look like anything familiar to their imagination...?
For example, They named Chimney Rock in Nebraska, Chimney Rock, because it does look a lot like a chimney, and Hat Rock in Oregon, looks like a hat. Or maybe the rapids entering the Wallula Gap, during their time, were too intimidating, and the Lewis and Clark Expedition didn't have time to look up to discover the Twin Sisters? It "could" be that simple...couldn't it?
For example, They named Chimney Rock in Nebraska, Chimney Rock, because it does look a lot like a chimney, and Hat Rock in Oregon, looks like a hat. Or maybe the rapids entering the Wallula Gap, during their time, were too intimidating, and the Lewis and Clark Expedition didn't have time to look up to discover the Twin Sisters? It "could" be that simple...couldn't it?
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The Twin Sister's are the guardians of the northern enterance of the Wallula Gap... 
...while Hat Rock is the guarian of the southern exit. Both features watch over the movement of the mighty Columbia. Both features are testiments to a once sudden violent earth changing flood. If only they can talk...
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Could huge floods on a Missoula Flood scale happen again? Although global warming may now be a serious concern, it is likely that long-term climate cycles will cause large ice sheets to return at some time in the distant future, and cataclysmic outburst floods will probably recur in this region...once again.
Just outside the boundaries of Hat Rock State Park this rustic, long forgotton, cattle farm stands exhausted against the test of time. I wanted to capture it before it eventually dissappears.
