The sources of the Columbia River cover 259,000 square miles and elevations up to 14,408 feet above sea level. Wallowa Lake is shown below nestled

in the ancient Wallowa Mountains of

eastern Oregon. Ray Atheson photo

The uplift resumed the last 70 million years or Cenozoic Era. The extinction of the dinosaurs probably resulted from the rising of the second Rocky Mountains - marking the beginning of the second major uplift. The new Rockies were formed about 72 to 43 million years ago, followed much more recently by the Cascades and the Coast Range. Heat created by pressure between the plates about 15 million years ago brought on the fire age. Lava flowed from long fissures in the Wallowa Mountains and along the line which later became the Cascade Mountains. It spread over 250,000 square miles in successive layers 10 to 40 feet thick, building to depths of 5,000 feet. The volcanoes of the Cascade Mountains appeared in the last few million years and many of the present cones were formed within the last 100,000 years. One collapsed only 6,600 years ago, Mount Mazama in Oregon, which now is topped by Crater Lake.

Mount Saint Helens, youngest of the Cascade volcanoes, is mentioned in the Indian legends as a beautiful maiden and alternatively an old hag. Now we know what the Indians meant. On May 18, 1980, the 9,677-foot cone, beautiful, symmetrical, and with a glistening mantle of snow, changed abruptly to a nondescript, barren rocky hump, torn open by a huge crater on its northern slope. The mountain had blown out its north side and top, devastating 156 square miles of Douglas fir forest, killing more than 50 people, burying Spirit Lake under many feet of ash, and

reducing the mountain's elevation to about 8,400 feet. Almost a cubic mile of ash, from this and subsequent eruptions, choked the Toutle and Cowlitz Rivers, which in turn passed much of the mud into the Columbia. High altitude ash fell on Yakima and across eastern Washington, and some in northwestern Oregon, including Portland. Traces of ash appeared across the country to the Atlantic. Early damage estimates exceeded a billion dollars.

The Cascade Mountains created a dike landlocking several large inland seas. Although the Cascades were repeatedly eroded and rebuilt, they continued to intercept the westerly winds, capturing much of the moisture. The inland lakes dried up. The land turned into desert.

Then came an ice age. For at least a million years ice covered as much as one-fourth of the earth's land surface, reaching a depth of 10,000 feet in Canada. Glaciation lowered the oceans by 250 feet. River channels extended further into the ocean, 20 miles in the case of the Columbia River. The ice oscillated, repeatedly receding and advancing every 10 or 20 thousand years, particularly at the continental ice margins as in British Columbia and northern Washington. The land bridge in the shallow Bering Sea

Steamboat Rock appears in the small picture looking south down the 30-mile long Grand Coulee in north central Washington. As recently as 20,000 years ago a huge glacier blocked the

Columbia River and raised its waters

300 feet above the top of the present day Grand Coulee Dam. The overflow carved out the Grand Coulee.

permitted animals and humans to migrate from Asia to North America via the Yukon River Valley and to penetrate southwards when the ice receded enough to permit travel.

Melting glaciers brought on floods. The last glacial age had blanketed northern Washington, Idaho, and Montana. An ice lobe across Pend Oreille Lake in Idaho to the Bitterroot Range dammed Missoula Lake, covering 3,000 square miles with water up to 2,000 feet deep. Another lobe blocked the Columbia River, raised its level, and diverted the water through Grand Coulee and over Dry Falls.

From time to time the ice dam holding Missoula Lake failed and released the lake's entire contents of some 500 cubic miles of water in 2 or 3 days. Geologists tell us that the last great flood occurred 18,000 to 20,000 years ago. It sent water down the Spokane River Valley at some 45 miles an hour, and across eastern Washington to Wallula Gap on the Columbia River. This and earlier floods created the scablands of eastern Washington. Another major channel continued to carve out Grand Coulee and erode Dry Falls. Thus, the powerful, and usually simultaneous, forces of uplift, fire, ice, and flood, combined with erosion. and sedimentation, created the physical Pacific Northwest.

The Land. The resulting land was mostly mountainous and uninviting, interrupted by barren deserts, then more mountains, and bordered to the ocean by thick forests. The Pacific Northwest includes the states of Washington, Oregon, Idaho, and western Montana. The 10,000-foot Rocky Mountain peaks mark the Continental Divide. From the rooftree of the continent the region slopes westward to the Pacific Ocean. Down this slope flow the waters that make up the Columbia River.

The eastern part of the Pacific Northwest features steep mountains, rugged foothills, and precipitous canyons, including the nation's deepest - the Hells Canyon of the

Snake River. The mountain streams provide the headwaters of the Columbia River and its major eastern tributaries, the Kootenai, Clark Fork, and Snake Rivers. The Columbia and Kootenai, however, rise in Canada. The eastern zone includes three national parks, Glacier, Yellowstone, and Grand Teton, and extensive wilderness, scenic, and recreational areas.

The central zone extends eastward from the Cascade Mountains about 200 miles, and 500 miles north and south. It comprises the relatively flat lava plateau at elevations from 1,000 to 4,000 feet above sea level. When irrigated the well-weathered basalt supports an extensive agriculture.

The Cascade Mountains, averaging about 40 miles wide in Oregon and 80 miles wide in northern Washington, reach from Canada to California. The range extends 100 miles into California to Lassen Peak and 50 miles into Canada to Mount Garibaldi. The Cascades in Oregon and Washington includes three national parks, Rainier, North Cascade, and Crater Lake, and many wilderness and recreation areas. Fifteen snow-covered volcanic peaks, some girded with glaciers, make the Cascade Mountains a wonderland of America. The Cascades divide the region between the moderate weather of the humid coastal strip and the dry continental climate to the east.

The hundred mile wide maritime strip reaches from the Pacific Ocean to the Cascades. The maritime climate results from the moderating influence of the Japanese Current cooling the coast in summer and warming it in winter. The coastal zone, south of the Olympic Mountains, provides for a prosperous agriculture and lush forests of fir, hemlock and cedar. Over half of the region's 7 million people live here, mainly in or near Seattle and Portland. The Willamette and Cowlitz are major tributaries of the Columbia.

The Water. The Columbia River watershed generally coincides with the boundaries of the Pacific Northwest. The Columbia River serves as the main factor in unifying and defining the region and constitutes the outstanding natural resource of the region. Of the 259,000 square miles in the Columbia River basin, 39,500 or 15% of the area lies in Canada. Except for the coastal streams of Washington and Oregon, the Columbia River drains the entire region.

Its average annual discharge of 180 million acre-feet makes the Columbia the fourth largest river in North America, after the Mississippi, Mackenzie, and St. Lawrence. Originating in Columbia Lake in British Columbia at 2,650 feet elevation the Columbia flows 1,210 miles to