Geology 101

The towns of Connell, Kahlotus and Washtucna are located in the bottom of Washtucna Coulee and are major players in my wheat country project. What is a coulee you might ask? Well… The Columbia Plateau is etched with deep, steep sided channels in the many layers of basalt that form the base of much of eastern Washington. During the last ice age, about 12,000 years ago, western Montana lay beneath lakes nearly 2,000 feet deep formed by a series of ice age glacial dams. Periodically the dams weakened until water burst through in catastrophic floods that raced across Idaho, Oregon, and Washington toward the Pacific Ocean. The floods carved the deep channels and scablands of eastern Washington. These channels are called coulees. They are steep sided with layer after layer of exposed columns of basalt and some with wide flat bottoms. The best known is the Grand Coulee but there are several others including Washtucna and Lind Coulees where most of my wheat county photographs were taken.

Between coulees are areas of flat or gently undulating land. Some spots have so little or no soil and crumbling basalt shows through (leading to the term channeled scablands). Other regions have accumulated sufficient soil to allow the cultivation of crops such as wheat if you have people with enough skill and gumption to do so. Although it is not always obvious and seldom if ever shared with outsiders, I strongly suspect that those that succeed here must also have a strong sense of humor. [Sorry if this sounds like a lecture, you will not be tested over any of the material in this post.]


EW720058-Edit - © Skip Smith Aggregate Pit and Grain Bins - © Skip Smith

Washtucna Coulee                                      Grain Bin & Gravel Pit

Washtucna Coulee is looking across the coulee and shows the layers of basalt and the Big Sage, which covered most of the region before agriculture. Grain Bin and Gravel Pit is looking at the bottom of the coulee. The old highway used to run along the bottom of the coulee. These photos were taken from nearly the same vantage point.



Dry Falls is in Grand Coulee and is the remains of the largest waterfall in the world. The cataract was 3.5 miles wide and dropped 400 feet.






5NegScan018        5NegScan016

Frenchman Coulee Overview                       Crumbled Basalt

Frenchman Coulee Overview and Crumbled Basalt (Frenchman Coulee) is a favored climbing area for those much more agile and younger than me.


Moses Coulee shows a portion of the north rim with the large accumulations of talus at the base of the basalt rim.


Palouse Falls is a spectacular falls in a coulee gouged out by the ice age floods.

It is just south of Washtucna Coulee.

This article has 2 comments

  1. Martha

    This blog of Coulee et al. is lovely, lovely. Your narrative — a combo of historical and scientific information — adds such a great element to your already beatiful and stand-along phontographs. I am so happy that you’ve added in the writing. Martha

Leave a Reply to Martha Cancel reply

Your email address will not be published. Required fields are marked *

Please send me an email for general inquiries, friendly hello's, or to contact me for print purchase. All pieces are available. Thank you for your interest! –Skip