North Cascades National Park
Although Sourdough Mountain is far from the tallest peak in North Cascades National Park, it is only 6,106 feet high, its summit seems like the top of the world. That is only partly because you must make a steep five-mile climb to reach its crowning snowfields, rocky ridges, and meadows open to the sun. Mostly it is because of the view. Located near the center of the park, Sourdough is completely surrounded by jagged peaks. Glaciers glisten in the bright sunshine, contrasting sharply with the gray rocks that cradle them. Below the craggy pinnacles, dark green forests cover the slopes like a rough-textured blanket.
Sourdough's summit, in fact, overlooks nearly all of the park, which includes hundreds of peaks, each with its own distinctive character. Sourdough, with its flower-filled meadows, for instance, is parklike and inviting. At Sourdough's foot, like Pumpkin Mountain, forested from top to bottom, seems meek and insignificant. To the south, Forbidden Peak, rocky and rimmed with several immense glaciers, looks every bit as cold and threatening as its name implies.
In the valley bottoms far below, streams and rivers streak like twisted ribbons. To the north of Sourdough the stretch of blue extending like a crooked finger toward the Canadian border is Ross Lake. The lake fills the bottom of the Skagit River valley, one of the deep, wide Cascade valleys that were carved out long ago by massive glaciers.
Even today, many Cascades peaks remain garlanded by glaciers. Though small compared with the giants of old, still the sparkling masses of ice are a major feature of this awesome landscape. Scientists count a total of 318 glaciers in the park, nearly one-third of all the glaciers in the United States south of Alaska.
As the glaciers melt, tiny rivulets form at their margins and begin their long journey from the barren highlands to lush lowland valleys. A spectacular example of the birth of a mountain stream can be seen below Mount Shuksan's Sulfide Glacier. Rivulets emerging all along the edge of the ice intertwine and merge, forming a lacy network of white water cascading down the mountain's stark, gray, rocky face. Just above the timberline all the rivulets unite to form a single stream that hurtles down a gigantic roaring waterfall.
This single stream rushes through the forest, growing each larger as it is joined by similar streams flowing down from Shuksan's glaciers. When it enters a pool, the frothy white water slows down momentarily and turns light green. Then the brush-covered banks close in again, and the water speeds through, churning white once more. At the valley bottom several streams converge to form Sulfide Creek, which roars as it rushes down the slope. Dull thunks punctuate the din as the current tumbles big rocks against one another.
Almost anywhere along the way a water ouzel, or dipper, may appear and supply a delightful sign of life. Flitting to a rock, the little bird sings a few staccato notes that resound above the roaring water and does a curious, curtsylike jig before plunging into the stream, where it walks along the bottom in search of food.
Finally Sulfide Creek merges with the Baker River, which carries Shuksan's meltwater, through the Skagit, to Puget Sound. During the transformation from rivulet to river, Sulfide Creek speeds through a varied landscape, the result of the Cascades' high landmass and steep slopes. Here, as on mountains everywhere, the climate grows harsher with increasing elevation. Thus the tall Douglas firs and hemlocks of the lowland forests gradually give way to smaller trees, such as Pacific silver fir, at middle elevations. Still farther up the slopes, scattered groves of hardy subalpine and alpine trees, mountain hemlock is an example, take over, then yield in turn to flowered meadows. Finally, in the high country where it is so cold that snow remains on the ground most of the year, only a few scattered patches of moss campion and other ground-hugging little alpine plants are able to maintain a hold on life.
The mountain range as a whole creates an even more startling climatic contrast. Moist prevailing winds from the Pacific flow up over the western slopes, cooling as they rise and releasing their moisture as rain and snow. Beyond the crest, the air descends and warms, dropping relatively little precipitation.
As a result, the west side of the range wears a lush, green mantle of tall trees and tangled undergrowth. Forests on the eastern slopes are more diminutive, with far scantier vegetation. The Douglas fir, which grows to towering heights on the west side of the Cascades, for instance, may grow only half as tall on the east side. And the moisture-loving hemlocks of western slopes are replaced in the east by ponderosas and other pines that tolerate much drier conditions.