Part 2

Glaciation

Other important geological events started about a million years ago. As the climate of the world became colder a great ice sheet formed to the north and moved down across Canada into the United States. There were periods when the climate warmed and the ice retreated. It advanced again when temperatures lowered during tens of thousands of years. The sheet moved southward at least four times during the last million years.

At the same time, valley glaciers flowed out of the mountains of British Columbia, joined forces, and formed a piedmont glacier that moved southward into Puget Sound and against the eastern edge of the Olympic Mountains. A lobe of this glacier branched off and flowed westward through Juan de Fuca Strait. This piedmont glacier, at least 3,000 feet thick, rubbed the northern edge of the Olympic Mountains and sent ice fingers up the valleys. It brought granite boulders from the north and dropped them along the way when it melted. Some of these granite boulders have been found near Camp Wilder, 25 miles up the Elwa River Valley, and as high as 3,000 feet on the side of Klahhane Ridge.

As the ice moved west along the northern border of the mountains, it plowed and scraped the deepened and ancient valley that filled with water when the ice melted. This valley contains Lakes Crescent and Sutherland. These and numerous other telltale marks attest to the work of a thick ice sheet.

Approximately 11,000 years have elapsed since the retreat of the last northern ice sheet from Washington.

With the onset of colder climate, valley glaciers also formed in the Olympic Mountains. They flowed from high mountain cirques down the valleys, probably filling the valleys during times of greatest ice volume and becoming thinner and shorter during times of warmer climate. Like the larger ice sheets from the north, the valley glaciers of the mountains must have advanced and retreated periodically. The greatest advance was as much as 25 to 40 miles in the Hoh, Queets, and Quinault Valleys. A terminal moraine left by a glacier dams Quinault Valley and holds the lake behind it.

The Shape of the Land Today

Knowledge of the geological history of an area enables us to better understand the shape of the land today. It will be recalled that earth movements depressed the land on the north, south, and east, leaving the Olympic Mountains standing alone, isolated from other mountains. However, they are a segment of that elongated western fringe of mountains known as the Coast Range. In all that range the Olympics are the highest; yet, for western mountains they are not high, dominating Mount Olympus being only 7,965 feet above sea level. This is not to suggest, however, that the Olympics are small. These mountains have their base at sea level, or not much above, and viewed from any lowland position they appear impressive indeed. A mountain climb will confirm this idea of their size.

The Olympics are not a single range of mountains but a profusion of peaks and ridges with intervening valleys—a mountain dome 60 miles across from north to south and east to west, cut by glaciers and numerous streams into rugged peaks and steep-walled valleys. There are nearly a hundred named peaks in Olympic National Park.

Mount Olympus occupies a central position on the Peninsula. To the west the ridges descend gradually and merge with the coastal plain which varies from a few to 20 miles in width. The eastern half of the Olympics maintains a high elevation all the way to the eastern edge. There they drop steeply to Hood Canal, an arm of Puget Sound, leaving but little lowland on that side of the Peninsula. The mountains end abruptly on the north side, too, but with some foothills between them and the shores of Juan de Fuca Strait, some 3 to 6 miles distant. Except for the western slopes, the ridges have a fairly uniform elevation of between 5,000 and 6,000 feet, and the peaks rise 1,000 to 2,000 feet higher.

The Olympic high country shows the effects of glacier scouring everywhere. Numerous lakes lie in basins that were scooped out by the same glaciers that carved circular hollows at the heads of valleys. Slopes sweep upward from the basins with increasing steepness and in many places end in serrated rock ridges and pinnacles.

More than a dozen streams flow out of the Olympic Mountains, returning rain and melt water to the ocean. They drop down steeply from the high level basins; after a few swift miles they flatten out and the water takes a slower pace.

Glaciers Today

A glacier is an accumulation of ice large enough to move of its own weight. Mountain glaciers form at high altitudes where snowfall exceeds melting and the snow builds up annually until, largely due to its weight, the lower layers become solid ice. When the depth of this ice becomes great enough—100 feet or more—it will flow down slope and the ice is transported to lower altitudes where warmer temperatures cause the ice to melt. The glacier terminates where this melting equals the amount of ice moving down from the area of accumulation.

The glaciers in the Olympic Mountains today are small indeed compared to the extensive glaciers that formerly filled the valleys and sculptured the mountains. The shape of the land testifies that a greater number of glaciers once were here. However, more than 60 glaciers, having a collective area of at least 20 square miles, are present today in the Olympic Mountains. Mount Olympus alone has 6 major glaciers, and the total area of permanent snow and ice on it is more than 10 square miles. Several other mountains also have glaciers, notably Mounts Anderson, Christie, Tom, and Carrie.

In addition, there are numerous snow patches that remain from one winter to the next but are not thick enough to form glaciers. Viewed from a high position, a panorama of north-facing slopes presents a profusion of snow and ice patches. The presence of so much snow and ice in mountains of modest height does not mean they are enveloped with inhospitable cold. It is due to the abundance of winter snow and considerable cool weather which retards its melting.

Glaciers are very sensitive to climate. Even slight changes in snowfall or temperature can cause them to advance or recede. Most glaciers everywhere have been shrinking during the past century. In recent years, western Washington climate has been cooler and wetter. As a result, many glaciers in this region, including Blue Glacier, have enlarged slightly.

Climate and the Water Cycle

Of all inorganic substances, acting in their own proper nature, and without assistance or combination, water is the most wonderful. If we think of it as the source of all the changefulness and beauty which we have seen in clouds; then as the instrument by which the earth we have contemplated was modeled into symmetry, and its crags chiseled into grace; then as, in the form of snow, it robes the mountains it has made, with that transcendent light which we could not have conceived if we had not seen; then as it exists in the foam of the torrent—in the iris which spans it, in the morning mist which rises from it, in the deep crystalline pools which mirror its hanging shore, in the broad lake and glancing river; finally, in that which is to all human minds the best emblem of unwearied, unconquerable power, the wild, various, fantastic, tameless unity of the sea; what shall we compare to this mighty, this universal element, for glory and for beauty? or how shall we follow its eternal changefulness of feeling? It is like trying to paint a soul.—Ruskin

The earth’s supply of water is fixed—it is used over and over again. What falls on land as rain or snow runs off, evaporates, or sinks into the ground. That which sinks into the ground may return: (1) to the air, by transpiration from plants and by evaporation from soil; and (2) to the sea, as ground water either flowing into streams or directly into the sea. All water falling upon the land eventually returns to the sea or to lakes whence it came. It evaporates and precipitates again and again. This continuous round of moisture is known as the hydrologic, or water, cycle. It is impressively demonstrated in the Olympics.

Salt water borders the Olympic Peninsula on three sides. Lowland on the south completes the isolation of the mountains. From atop some mountain peaks one can see the Olympic water cycle in its entirety—ocean, “cloudscape,” snowfields, glaciers, streams from source to mouth returning water to the sea, and forests transpiring moisture into the air.

A landscape is an expression of climate. The Olympic landscape, with its rain forests, snowfields, glaciers, lakes, and numerous streams in deep valleys, is a superb expression of a superhumid climate. Abundant water is the prime source of Olympic’s character. The prevailing on-shore winds acquire much moisture in passing over the ocean. The windward slopes of the Olympics cause this nearly saturated ocean air to rise. Consequently, the western slopes of the Olympic Mountains receive the greatest precipitation in the conterminous United States.

The Hoh Ranger Station has a mean annual precipitation of 142 inches, with 174.6 inches recorded in 1961. Precipitation on Mount Olympus recorded in 1958 was 149 inches but this same year only 130 inches were received at the Hoh. Scientists who have been studying Blue Glacier on Mount Olympus since 1957 believe the heads of the western valleys receive 200 inches in some years.

Marine climates have greater precipitation in winter than in summer. Seventy-six percent of the yearly precipitation in northwest Washington occurs during the 6 months between October 1 and March 31. There is no definite time for the beginning and ending of the “dry” and “rainy” seasons, as the transition is gradual and variable.

The Olympic Peninsula would be well watered even if there were no mountains. The mountains, however, are responsible for wringing the bulk of the moisture from the saturated clouds and for creating local variations in the amount of precipitation. After passing over the mountains, the air is warmed in descending the leeward slopes. Consequently, the lowland areas on the lee side of the mountains are much drier than on the windward side. For instance, on the Olympic Peninsula at Sequim (pronounced Squim) the mean annual precipitation is less than 17 inches, and irrigation is required for successful agriculture.

Another prominent characteristic of the climate is the mildness of the winters at low elevations. In fact, western Washington is milder in winter than any other section of the continent in the same latitude. The reasons for this are the warming influence of the ocean and the protecting influence of the Cascade Mountains and of the Rocky Mountains against the flow of cold continental air westward to the coast.

Storm centers that pass eastward across Washington in winter shift to the north in summer, resulting in sunny summer weather that is delightfully cool under the influence of the ocean.

The Forests and Wildflowers