Olympic Mountains Trail Guide. Robert Wood

are long and unbroken, but others have been eroded into sharp peaks and hanging valleys, truncated spurs and glacial cirques.

      The creation of the Olympic Mountains occurred about 120 million years ago, when the land that now constitutes the Olympic Peninsula lay under a shallow sea. The peninsula has been alternately submerged beneath the sea or uplifted above it on at least five occasions, with erosion following each of the uplifts. The final rise occurred when the Puget Trough was depressed, leaving the mountains bordered by lowlands. The present-day mountains are composed of rocks that range in age from 15 million to 55 million years, thus in geologic terms the mountains are young. This uplift is chiefly composed of sandstones and shales that are closely folded and have been increasingly altered toward the interior. However, a horseshoe-shaped band of basalt encloses the mountains on all sides except the western. This band is thickest and widest in the east. Both the sedimentary rocks and the basalt were formed beneath the ocean—the former by deposits on the ocean floor, the latter by undersea lava flows. The only granite found in the Olympics, despite the reports of pioneer prospectors, is in the form of glacial erratics—boulders carried down from Canada by the Cordilleran Ice Sheet.

      According to plate tectonics, the Olympics were uplifted by the movement of oceanic plates against and beneath the continent, which is not in agreement with an earlier theory that the mountains are the remnants of an upthrusted dome. Nevertheless, they do have a discernible dome-like appearance. Although the Olympics are geologically similar to the coastal chain of mountains found along the western margin of North America, they are not part of it, having been uplifted at a separate time.

      The Olympics were sculpted by alpine glaciers during the last ice age. The ice carved its way down the precipitous slopes, transporting debris which was deposited at lower elevations. Subsequently, the Cordilleran Ice Sheet from Canada pushed into the basin between the Cascades and the Olympics. One ice lobe moved westward along the Strait of Juan de Fuca, another thrust southward down the Puget Trough. The ice sheet then retreated, but large alpine glaciers remained on the higher peaks.

      The climate following the end of the ice age was mild for about three thousand years, and subtropical conditions extended as far north as Canada. During this warm period—which occurred about ten thousand years ago—the alpine glaciers retreated, postglacial erosion took place, and forests began to invade the country where the ice had prevailed.

      The largest glaciers existing today in the Olympics—chiefly the ones on Mount Olympus and Mount Anderson—are believed by some geologists to be survivors of the ice age, but the smaller ones found throughout the Olympics are thought to have been formed during a subsequent cooling period—the so-called Little Ice Age of historic time, three thousand to five thousand years ago. Glaciers still exist on the higher peaks today, and the Olympics are noteworthy for having the lowest snow line in the United States (excluding Alaska). This line is the elevation above which snow can be found year-round. The largest glaciers in the range today vary from 1 to 3 miles in length. Although glacial carving is most pronounced on the northern and eastern sides of the mountains, all the larger valleys and canyons have been deepened and steepened by glacial erosion.

      STREAMS AND LAKES

      The rounded, dome-like configuration of the Olympic Mountains has resulted in a pattern of rivers that spiral outward from the central heights. These rivers, numbering perhaps a dozen having major significance, flow in all directions—west to the Pacific Ocean, east to Hood Canal (an arm of Puget Sound), north to the Strait of Juan de Fuca, and south into the Chehalis River drainage. Beginning in the north and proceeding clockwise around the mountain uplift, the major rivers are the Elwha, Dungeness, Quilcene, Dosewallips, Duckabush, Hamma Hamma, Skokomish, Wynoochee, Humptulips, Quinault, Queets, Hoh, Bogachiel, and Sol Duc.

      The rivers are all short, but they rapidly carry enormous quantities of water to the sea because the precipitation on most of the peninsula is excessive. When the streams are in flood, they lose their normal clarity and roll along at high speed. At this time they are dangerous to cross, but they should always be treated with respect. Flooding occurs after heavy, sustained rains and when the snowmelt reaches its maximum in late spring and early summer. At this time the tributary creeks, unrestrained and brawling, as they flow through deep, narrow canyons, clatter like freight trains racing across the country.

      The Olympic Mountains have many lakes, most of them located in the higher elevations. With the exception of five at low elevation—Ozette, Crescent, Quinault, Sutherland, and Cushman (which technically is a reservoir)—they are small and were created in various ways, including by glacial activity and dam building by humans. Most of the lakes are cold, but a few are warm enough to permit bathing. The lakes in the high country, at timberline or above, generally are thawed out and open by mid-July, but after winters of excessively heavy snowfall, if followed by a cool spring or summer, they sometimes remain frozen until mid-August. At this time many of the adjacent meadows—particularly on northern, shaded exposures—are still covered by a foot or two of winter’s snow while flowers bloom on southern slopes facing the sun.

      VEGETATION ZONES

      In mountainous regions, a phenomenon known as altitudinal zonation is present, caused by climatic changes that occur with an increase or decrease in elevation. As the elevation increases, the temperature decreases, and the climate becomes harsher, which has resulted in a classification called vegetation zones. Four such zones are present on the Olympic Peninsula—the Lowland Forest Zone, the Montane Forest Zone, the Subalpine Zone, and the Alpine Zone.

      The Lowland Forest Zone ranges from sea level upward to elevations varying from 1500 to 2000 feet. This zone not only covers the lowlands surrounding the Olympics but also extends deep into the mountains by following the major rivers, gradually phasing into the Montane Forest Zone, which extends from the upper limits of the Lowland Forest Zone to an elevation about 3500 feet above sea level. The Subalpine Zone occupies the territory between the upper limits of the Montane Forest Zone and approximately the 5000-foot level. Above it, the Alpine Zone extends upward to the summits of the highest peaks.

      Like everything in nature, the vegetation zones do not have distinct boundaries; instead, they blend into one another in an irregular manner. On cold northern slopes, for example, the Subalpine Zone at times extends well below 3500 feet. On the other hand, mountainsides with southern exposure often exhibit Montane Forest Zone conditions above 3500 feet. At times the Alpine Zone occurs at elevations below 5000 feet, particularly in the vicinity of glaciers.

      On the peninsula, the Lowland Forest Zone has a mild marine climate, one typical of sea level at this latitude (45 degrees to 50 degrees north of the Equator). Within the mountains, this zone dominates the river bottoms and the lower foothills. The principal conifers are Douglas-fir, western hemlock, western red cedar, and Sitka spruce. Deciduous trees include red alder, bigleaf maple, black cottonwood, and Pacific dogwood. The luxuriant forest floor exhibits green mosses, flowering plants, and bushy shrubs. Included among the latter are willow, red elderberry, salmonberry, salal, huckleberry, devil’s club, and rhododendron. Low-growing plants include Oregon grape, skunk cabbage, fireweed, and many kinds of ferns. The luxuriance of this zone contrasts markedly with the dark, gloomy stands of the Montane Forest Zone on the slopes directly above. Elk herds live here the year around but particularly in the winter. Deer, bear, and cougar are also present. The bird life is varied—kingfishers and dippers on the streams, wrens and varied thrushes in the deep forests.

      The Montane Forest Zone is largely confined to steep mountainsides, and the temperature is usually somewhat cooler than on the lowlands. This is a realm of dense, somber forests, mostly thick stands of tall conifers. The common trees are Pacific silver fir, western hemlock, and Douglas-fir, with a sprinkling of western white pine and western red cedar. Because the trees grow in heavy stands, and their crowns interlock, the sunlight that reaches the ground is soft and indirect, the air cool, fragrant, and moist. In fact, this canopy is so dense it intercepts the first winter snows, which often melt on warm succeeding days, never having reached the earth. On the steeper mountainsides, pistol-butted trees may be observed. Occasionally this results from ground creep, but the phenomenon is more often caused by heavy snow that bent the trees when they were young and pliable. Undergrowth