Sunday, May 21, 2017

Frenchman Coulee

I sort of knew this place was here, but never appreciated how close it was to I-90. A 15-minute side trip at the Silica Road Exit would be enough time to check out the view and still make it back to the freeway.

Fortunately, I had more than 15 minutes, so I drove all the way down to the river. I guess this was the route of the old road across the river to Vantage, before the Wanapum Dam was completed in the early 1960s and this part of the valley was flooded. The climbers were out - I also hadn't realized what a climbing mecca this was. Bicyclists were riding down to the river and back. Folks were camped along the way and cars were parked at the trailheads.

And a CWU Geomorph class was getting introduced to the role of the Missoula Floods in creating this landscape. There were many outburst floods from Lake Missoula, but they didn't all take the same route across central Washington (depending a little on which portions of the river were still blocked by ice). But many came down Grand Coulee (over Dry Falls) and then spread out across a broad fan below Ephrata. From there, they took several several paths into the Columbia Valley - including here at Frenchman Coulee and just north at Potholes Coulee (where I went next). The huge floods flowed over the cliffs, plucking and eroding out the basalt, head cutting the flat-bottomed coulees.

In the past, I've posted from Lake Missoula (Gravel Beach: 2011) and Camas Prairie (hshipman: 2014) at the upstream end of this whole flood story.

After a long day trip to Steamboat Rock in 2011, I told myself I should try to get in at least one good excursion to eastern Washington every spring. But somehow it just doesn't happen. Not that I won't keep trying.

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