Yosemite National Park - Birds and Bears

Dancing Waters
Before the Sierra was lifted, the Merced's tributaries joined the river with scarcely a ripple. But as the mountains rose higher and tilted more abruptly, the Merced cut deeper, abandoning the side streams that were unable to match its cutting edge. Stranded atop steep, jagged slopes, the streams cascaded from ledge to ledge on their way to the river. When the glaciers advanced on the valley, they sheared the slopes into nearly perpendicular walls, truncating the side streams even more. Now they were free-falling cataracts whose colossal heights punctuated the valley walls like watery exclamation points.

Known as "the place of dancing waters," Yosemite Valley is the perfect stage for an aquatic ballet of rainbowed waterfalls leaping, twirling, prancing from lofty chutes, and pirouetting from cliff to cliff. In spring, the performance becomes a full-blown extravaganza as snowmelt enlivens hundreds of streams that rush to join the regular cast in a magnificent aerial display. To be sure that their show does not pass unnoticed, the performers send up a thunderous roar that resounds throughout the valley. Unfortunately, the dance ends all too soon. By mid-August, most of the falls are bone-dry. Autumn rains renew some to wispy tendrils, and sunny winter days may start a bit of meltwater flowing; but frosty nights ice the ledges and turn the falls into frozen columns. One must wait for the melting waters of the next spring thaw for an encore.

More than half of America's highest waterfalls occur in this park, but because you generally see them from afar, it is difficult to hell how big they truly are. Trying to estimate their height or width is like guessing a star's size in the vastness of the heavens. Snow Creek and Sentinel falls are 2,000-foot cascades that tumble down ridged granite; Ribbon Fall, the park's highest single waterfall, is a white-water rocket dropping 1,612 feet. Bridalveil Fall, which never runs dry, plunges 620 feet, and a grand and graceful rainbow often sweeps across its diaphanous mists. Even the 300-foot midgets are impressive. In any other place they would undoubtedly reign as monarchs, but here everything is measured against the champion Yosemite Falls, highest in North America and second highest in the world. The 2,435-foot waterfall, equal in height to 13 Niagaras, descends in two thunderous phases: the Upper Fall drops 1,430 feet; the Lower Fall, 320. In between is a series of cascades that leap from one level to the next, whipping the water into a frenzy, splashing and spraying the sides of a quarter-mile gorge. From below, Yosemite Falls seems like one continuous waterfall, mighty and magnificent, a symbol of nature's power unleashed.

The falls eventually feed into a sometimes placed, sometimes stormy waterway that Spanish explorers named El Río de Nuestra Señora de la Merced, meaning "The River of Our Lady of Mercy." Beginning as a swift creek, the Merced first tumbles haphazardly down the Giant Stairway, a mountain slope with glacially carved steps. But after it roars down Nevada Fall, it becomes a river dashed to foam, a wild, aquatic avalanche that surges toward yet another swelling cascade, Vernal Fall. In just a half-mile stretch, the Merced drops 1,200 feet. Once the river levels out on the valley floor, it becomes little more than a lazy meander with riffled edges and deep, quiet pools, a sparkling blue thread winding its way down the long-forgotten corridor of ancient Lake Yosemite.

A Vanished Lake
The prehistoric lake had come and gone many times: meltwater from glacial withdrawals gave it life; glacial advances dried it up. When the climate finally warmed and the last glacier retreated upslope, meltwater once again filled the valley, re-creating ancient Lake Yosemite in all its glory. Stretching from wall to wall and almost seven miles in length, the lake was impounded on the east by Half Dome and on the west by a pile of rocky debris left by the glacier.

If time and the river had not obliterated Lake Yosemite, it would have been a world-class contender, a sapphire mirror reflecting majestic mountain walls, the play of light on granite, and ragged-edged clouds skimming the heights. But Lake Yosemite was not to last, for the very forces that gave it life insured its demise. As the two major watercourses, the Merced River and Tenaya Creek, dumped tons of sand and gravel into the lake, deltas began to form, and these gradually expanded, merged, and spread down the valley. The lake grew shallower and shallower and eventually began to shrink. Water-loving plants colonized the borders, gradually building up the soil so that meadow grasses and wildflowers could take up residence. The lake dried up and disappeared. With a solid earthen base firmly established, trees put down roots and became permanent settlers.

Nature is not quite finished with her long transformation. There are still a few grassy meadows holding out against the ever-encroaching forest. Trees continue to inch forward, but they are held in abeyance by the flooding of low-lying pockets each spring. A similar process is reclaiming Mirror Lake in Tenaya Canyon, northeast of Yosemite Valley, and one day this beautiful, gemlike lake, too, will be only a memory.