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Great Terrace of the Columbia #1 - The Explorers

Geologists have long been fascinated with the high terrace that stands well above the modern Columbia River between Brewster and Chelan. Its origin, composition, extent, and connection to other flights of terraces in the region (i.e., Okanogan Valley) is still a topic of debate. To my knowledge, no one has compiled what has been written about The Great Terrace in one place. So I'll do it here.

In this post I compile a record of writings on the terraces of the Columbia and Okanogan Rivers in north-central Washington. In short, the explorers' observations in their own words. Two additional articles will focus on Great Terrace geology (The Great Terrace #2 - The Geologists) and new geological research in the Okanogan Valley (The Great Terrace #3 - New Research).

David Thompson, the British-Canadian explorer of Welsh decent and his "Nor'Westers", in 1811, was probably the first white man of distinction to visit the mouth of the Okanogan River, on his way down the Columbia to the Pacific. Its unclear if Thompson was interested in geology beyond that which would practically facilitate his travels.

Captain G.B. McClellan, whose 1853-1855 exploration of the northern portion of the Washington Territory would identify suitable railway routes from Spokane to the Pacific, makes an early mention of a "Great Plain" at the confluence of the Okanogan and Columbia Rivers (in I.I. Stevens, 1855),

On the top of the lofty table of the Great Plain, opposite the mouth of the Okinakane, is a considerable extent of pine woods, several thousand feet above the Columbia, into which it could easily thrown or slid down, as the cliff is almost perpendicular.This is provably the high point of the plain, and is the point where a spur appears to cross the river and to sink into the level of the plain.

The north bank of the Columbia, between the Methow and Okinakane, is low, sandy, and barren, but rises into grassy slopes at a few mils distance, which towards their summits become covered with pine woods.

The Methow River, which was explored nearly to its sources, has a considerable extent of good agricultural and grazing land in its upper valley. Its lower part, for twenty miles up, is hemmed in by high wooded hills; above this, they become more rolling and grassy, and its banks are bordered by level wide terraces of better soil than those on the Yakima.

An Okanogan Valley cowboy at the Omak Stampede Grounds with a prominent glacial terrace in the background. The terrace serves as a race course. The Omak Suicide Race is a "no holds barred" horse race where riders begins on the flat terrace top, descend the steep escarpment to the Okanogan River, swim it, and gallop another 500 yards into the arena of cheering fans.

Naturalist J.G. Cooper from his journal of October 1853,

Camped at the Okanagan R. on the west bank. Obtained here specimens of four species of Artemisia making 6 seen in flower. Remained half a day to exchange horses with the Indians...Proceeded up the course of the Okanagan River 12-1/4 miles camping on its banks...This river is more slow & shallow than most seen & on its banks are some fine arable lands...This appears to be about the commencement of Autumn in this region, the deciduous trees turning brown & yellow & some of the early flowering plants are blooming again...Continued on for 15 miles up the river. Saw at camp great numbers of a species of Salmon, swimming up stream and nearly worn out by their long journey up stream their tails almost gone & bodies turned of a red color so that they are easily seen...Very few are said to return to the sea, after spawning & their carcasses line the shores of the Columbia in the fall, feeding multitudes of birds & quadrupeds. Dogs are often made sick so are rarely to recover after eating them...Continued on for 11-1/2 miles up the river passing the forks & encamped on the side of the fourth lake...Remained at the same place while a small party went to visit a lake to the north...I obtained here several fish (Carp?) the same as are caught in the Col. R. but no trout or Salmon were seen...

Alexander C. Anderson from his 1865 journal documents his journey for Western Union Telegraph,

The whole of the Okinagan valley is very practible, the chief portion consisting of sandy levels...The dry gravelly flats are interspersed with fertile bottoms in parts. The Prickly Cactus and the Rattlesnake attest the warmth and dryness of the soil.

Captain T.W. Symons, who assessed the Columbia's navigability, describes its overall character between the Spokane River mouth and Lake Chelan,

The general character of the country in the vicinity of the river Spokane to Chelan many be described in a few words. The river flows through a deep and rugged canon with very little bottom land along its banks. It can be approached from the Great Plain on the south only in three places: by the Virginia Bill road, Whitestone road, and Foster Creek. From the north it can be approached in more places, and generally wherever a stream comes in a good easy way exists of getting to the river. The country to the north has been very much more eroded than that to the south.

At Lake Chelan George McClellan observes,

Numbers of beautiful little streams put into the lake, and generally about their mouths there is a fine series of flats or benches. One which I recall to mind on the south shore of the lake, about twelve miles from the mouth, is one of the most beautiful places that I have ever seen.

Spokane River from mouth of Little Spokane River. J.G. McMacken (1937) photo.

Symons notes how the broad flats at Lake Chelan provided a pleasant camp for troops, but ultimately proved unworkable for a Territorial fort,

In the Spring of 1880, the troops which had been encamped at the mouth of Foster Creek for the winter, removed to Lake Chelan, and Camp Chelan was established just were the lake narrows into the creek, on a beautiful bunch-grass covered plateau on the north bank, stretching back about a mile to the rocky and timbered hills.

The chief drawbacks to this post were the terrible road getting down to the river from the Great Plain on the east, there descent being about 2,500 fee; the crossing of the river where there was quite a swift current; and the ascent of the hill to the lake.

Symons, upon reaching the mouth of the Wenatchee River observes,

This river, for the lower part of its course, flows through a level plain of fine agricultural land, containing from twenty to thirty square miles.

The Symons party passing Victoria Rock near Wenatchee with a skilled crew of Native oarsmen under direction of their excellent pilot-guide, Old Pierre. Symons recalls the crew's preparation for navigating the dreaded Rock Island Rapids, "Finally, after an animated discussion among them, it is decided, and all return to the boat and prepare for the removing gloves and all superfluous clothing and tying red handkerchiefs tightly about their heads. Choosing the right-hand channel, our boat hugs the right bank pretty closely, passing safely the upper ripple...I cannot praise them too highly for their skill, their uniform good nature, honesty, endurance, and sobriety. I think it would be very difficult to pick up at a few hours' notice four white men who would row a heavy boat through dangerous rapids for four hundred miles without wanting strong drink, or be able to withstand, after being paid off, the temptations of drinking saloons." - Symons (1882).

Symons at Lodgestick Bluff,

All along up the river, wherever there is a concave portion of the bluffs, there we find terraces of from ten to five hundred feet in elevation above their neighboring terraces below. These are all composed of rather loose soil, bowlders and gravel, and river sediment, and have well defined and sharp edges...would seem to prove their newness in the scale of time.

At Vantage,

The terrace formation so prevalent further north, here has almost entirely disappeared...the country opens out on the west into a broad flat, with rolling hills to the rear, while the [rocky] bluffs on the left bank keep getting lower and lower.

By Mattawa,

..the country becomes flat, sandy, and uninteresting, elevated but a little above the river.

Below Priest Rapids,

Very few objects of interest were to be seen. The country on each side is low, flat, and the soil appears sandy and unproductive. To the south the flat land extends away to the Yakima River.

At White Bluffs,

The river makes a semicircular sweep to the north and cuts into the bluffs, leaving a very nearly vertical wall from one hundred to six hundred feet in height. The rock is a sandy marl, soft and friable, which easily powders where the cattle have traveled over it in going up and down hill for food and water. We continued under these bluffs for ten miles or more.

The Great Terrace at the mouth of the Methow River near Pateros, WA. Matsura photo (#7326). Okanogan County Historical Society archive.

Ross Cox, the officer in charge of Fort Okanogan and a member of the first white party to visit the Okanogan Valley, notes,

The climate of the Okinagan is high salubrious. We have for weeks together observed the blue expanse of heaven unobscured by a single will in my opinion be selected as a spot pre-eminently calculated for the site of a town when civilization crosses the Rocky Mountains and reaches the Columbia.

Symons predicted the lower Okanogan Valley would attract considerable commerce, something that has not happened,

I am strongly of the opinion that the mouth of the Okinakane there is bound to be a commercial and manufacturing center at some time in the future, when the whole country is thrown open to settlement.

About nine miles from the Okinakane the Methow River comes in from the northwest. The country on the right bank of the Columbia between these two rivers consists of a succession of nearly level benches or terraces, some having very fertile and rick soil, and other being composed largely of sand drifts. These benches stretch away from the river to the time, which appears on the higher grounds about 6 or 7 miles to the rear.

He successfully predicts the future of TriCites,

At this point on the Columbia, at the lower end of Priest Rapids, must surely be located a town of considerable importance, as it will for a long time be the head of navigation on the river. It is the most convenient place from which to reach the Yakima and Kittitas valleys, which now communicate with the lower country by a wagon-road over the Simcoe Mountains to the Dalles. The rapids will furnish a splendid water power, and in all probability here will be located flour and saw mills, as well as warehouse and stores.


Terrace and wagonroad country. Matsura photo (#6626). Okanogan County Historical Society archive.

More to come as I find it...


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