The volcanic eruption of Mt. St. Helens, in southwest Washington State within easy viewing range of the Portland- Vancouver metropolitan area, has triggered an intense new interest in the natural forces of volcanism that have shaped the Pacific Northwest. Many are hoping the smoking, steaming mountain will provide some stimulation for the area's tourist industry this summer, prospects for which were looking a little grim because of gasoline prices and economic recession.
Ever since Mt. St. Helens first sent its plume of steam, smoke, and ash into the sky on March 27, volcanologists, geologists, earth scientists of all kinds, and just plain sightseers and tourists have flocked around the symmetrical volcanic cone. The mountain has relaxed into more subdued action since the first couple of weeks, but the show may go on for months.
While Mt. St. Helens provides an opportunity to see a volcano in action, the entire Cascade Range from California to northern Washington provides a string of volcanic sights that are the results of events in recent geologic times. And the sights are easily accessible to the most casual summer tourists.
Starting from Mt. Lassen in the south to Mt. Baker near the Canadian border in the north, the volcanic wonders of the Cascades are laid out for viewing on easy trips from Interstate 5 on the west side or US 97 on the east side.
Lassen Volcanic Nation Park surrounds Mt. Lassen. Lassen erupted in 1914 and remained active until 1921, the most recent volcanic activity in the continental United States until St. Helens got into the act. Lassen can be reached by major routes east from Red Bluff or Redding on I-5. Farther north near the Oregon border just south of Tulelake is the Lava Beds National Monument, a vast moonscape of broken lava where in 1876 human drama was added to the natural volcanic phenomena. Captain Jack and some 50 Modoc warriors held out here for months against the best the US Army could muster in the Modoc Indian War. Gen. E. R. S. Canby of Civil War fame was killed in that encounter, the only US general to lose his life fighting against American Indians.
In southern Oregon northwest of Klamath Falls in Crater Lake, one of the most splendid results of volcanic activity to be found anywhere. Enclosed in a rim that stands some 7,000 beet above sea level, Crater Lake is 2,000 fett deep and covers 21 square miles. The rim and the lake are what is left of a prehostoric Mt. Mazama, which was originally probably higher than 12,000 feet. Sometime within the past 7,000 years Mt. Mazama literally blew its top, spreading molten lava as far as 35 miles away and spewing pumice and volcanic debris over vast expanses of Oregon. Geologists estimate that 10 cubic miles of material was ejected. Then the sides of the narrow cone collapsed, leaving the wide caldera to fill with water. A subsequent eruption raised a perfect cone from the bottom. It now stands in the middle of Crater Lake as Wizard Island.
Farther north in Oregon, south of Bend and somewhat isolated from the main Cascade Range, stand the Paulina Peaks and Newberry Crater. This might have been a scenic duplicate of Crater Lake, except that the blowup of Paulina was less precise. Subsequent eruptions raised a ridge that separates Paulina Lake and East Paulina Lake.
Also south of Bend near US 97 are volcanic ice caves, where water trapped in lava caverns remains perpetually frozen; the Lava River Cave; and a bizarre forest of lava tree cast. Tha Lava River Cave was formed when a stream of molten lava flowing down a stream bed cooled around the bottom, the sides, and over the top. Tha lava continued to flow in the center and eventually left a lava tunnel about two miles long, 30 to 40 feet deep, and k0 feet wide. Water flow has subsequently deposited a floor of sand in the tunnel.
The lava casts were formed when lava surrounded full-grown trees and cooled. The wood inside burned or rotted away, leaving a forest of hollow lava trunks standing.
Along the crest of the Cascades between Eugene in the Willamette Valley on the west side of the mountains and Bend on the east side is the beautiful Three Sisters Wilderness Area, flanked on the northwest by the vast lava fields surrounding Belknap Crater. Volcanologists say that nowhere in the world are there such remarkable evidences of comparatively recent volcanism as are contained in this area of central Oregon.
The Three Sisters, three peaks of more than 10,000 feet, are the remains of a once-might mountain that may have been the biggest in the Cascades before it blew up in a cataclysmic eruption that surpassed those of Paulina and Mazama.
Belknap Crater was the source of probably the most recent major magmatic eruption in the Cascades. The vast jumble of lava that surrounds the crater can be viewed easily from the McKenzie Pass highway (state route 242) between Belknap Springs and Sisters.
All along the Cascades there are many other examples of volcanism. Some are as accessible as those listed and others are not.
All the peaks of the Cascades -- Baker, Rainier, Adams, Hood, Kefferson, McLoughlin, Thielsen, Shasta, St. Helens, Lassen, and many others -- are relatively recent volcanoes. These snowcapped spires create an awe-inspiring scene, even if the volcanism aspect is ignored.