12 February 2012

Western pearls

The Cascades and Sierras are like a string of pearls lying from north to south along the western edge of the United States: Mt. St. Helens, Mt. Hood, Crater Lake, Mt. Shasta, Tahoe, Yosemite, Sequoia. Over the last few years I have come to love these beautiful mountains. The white peaks of the Cascades are volcanic in origin and still active: the violent eruption of Mt. St. Helens in 1980 and the bubbling sulfurous mudpots found in Lassen National Park attest to this. Many of these mountains have a beautiful conical shape, like the revered symmetry of Mt. Fuji in Japan.

Mt. Lassen in northern California is the southernmost major peak of the Cascades. But topographically at least, the mountains continue to the south with the Sierra Nevada range. The Sierras tell a different geologic story than the Cascades. Some 250 million years ago, the collision of the Pacific and North American plates melted rock that formed under the ocean in plumes (1). These structures fused. Then about 80 mya, this massive chunk of rock pushed up through the ocean floor and carried the marine sediments that had been deposited on top. Asymmetrical uplift left the eastern side of the Sierras at a higher elevation, with a more gradual decline to the west. Subsequent erosion removed much of the marine sediment, and recent glacial activity carved elegant designs into the landscape such as the world-famous Yosemite Valley.

John Muir, the poet laureate of the Sierras, termed these magnificent mountains “the range of light”. In evangelical exuberance, which Muir used without hesitation in his description of wilderness, he described a view of Yosemite in the heart of the Sierras:


“It is easier to feel than to realize, or in any way explain, Yosemite grandeur. The magnitudes of the rocks and trees and streams are so delicately harmonized they are mostly hidden. Sheer precipices three thousand feet high are fringed with tall trees growing close like grass on the brow of a lowland hill …. Waterfalls, five hundred to one or two thousand feet high, are so subordinated to the mighty cliffs over which they pour that they seem like wisps of smoke, gentle as floating clouds, though their voices fill the valley and make the rocks tremble. … The mountains, too, along the eastern sky, and the domes in front of them, and the succession of smooth rounded waves between, swelling higher, higher, with dark woods in their hollows, serene in massive exuberant bulk and beauty, tend yet more to hide the grandeur of the Yosemite temple and make it appear as a subdued subordinate feature of the vast harmonious landscape. Thus every attempt to appreciate any one feature is beaten down by the overwhelming influence of all the others.” (2).


Just before the turn of the new year this winter, we took an adventure north to south down the eastern side of these magnificent mountains. We crossed the Cascades east of Eugene and once over the crest of the range, traveled from that point forward in high country on our trip to southern California. Passing through the Cascade Range in central Oregon, I was amazed once again by the dramatic shift in vegetation on either side of the divide. Dense coniferous forests with lush green understories dominate the western slopes of the Cascades, but the forests quickly change to drier, shorter and more open canopies vegetated by pines to the east. The change in forest type is, of course, driven by differences in precipitation on the eastern and western slopes. Storm clouds moving inland from the Pacific run into the mountains and dump most of their captive water before reaching the high country.

On this trip, it snowed briefly in southern Oregon near Chemult, but the skies lightened as we moved further south towards the Oregon/California border. In Modoc County (NE California), we entered the Great Basin floristic province. Here the vegetation became desert scrub peppered with juniper trees, the largest plants on the landscape. Small patches of snow remained on the ground. Our first significant stop was Lava Beds National Monument. The short winter day was drawing to a close but we explored two of the lava caves. They were cold wide shafts filled with rubble of very bland grey and pale colors; the caves relatively gradually descended downward into the earth. We saw no bats or other wildlife in the caves, but located some small ice sculptures adhering to the rocks below. The little sculptures were shaped like hemispherical ice cream scoops, having accumulated when water dripped from the cave ceiling above and apparently froze quickly as it flowed down the mound.

Visitors in a cave at Lava Beds National Monument


The next day, further south, the highway took us near Susanville and into Nevada for a time before crossing backing into California. We arranged for a stay in the small town of Bridgeport back on the California side of the border.

On day three we learned from a highway sign that several of the roads that traverse the Sierras that are typically closed to traffic during the snowy winter months were still open at this late season. This exciting news led to a quick decision to make a detour into the eastern end of Yosemite National Park. Access to Yosemite high country by car at this time of year was a real treat since National Park records indicate that Tioga Pass had not been open this late in the winter for at least the last 31 years! (3) Already at about 7000 ft elevation in the Mono Lake area, we made it up the pass to nearly 10000 ft towing our small rented trailer. Tioga Pass is a lightly vegetated gorge of granite and snow with strong winds that move down the canyon. On the less sun-exposed places to the south and deep in the canyon, ice froze in place to form suspended white and turquoise waterfalls.

Tioga Pass


At the top of the canyon, we encountered our first alpine lake (Ellery Lake), locked frozen into the mountains at 9538 ft. Further west into the park, we explored Lembert Dome, Tuolumne Meadows and Tenaya Lake. Near Lembert Dome, we took a hike through coniferous forest to Dog Lake. Like the other alpine lakes, this one too was frozen. We walked and shoe skated over the whitish-grey ice.

Dog Lake


In the afternoon we left Yosemite, heading back down Tioga Pass onto the east side of the Sierras in time for a sunset that painted clouds and mountainsides various colors. On day four we moved further south into the Owens Valley and started to encounter classic southern California desert habitat. Tufts of dried tumbleweeds were interspersed semi-regularly on sands and rubble on the grey landscape. Perhaps their phobia for neighbors was created by intense competition underground for the sparse water available in the desert. Here the landscape was open. Expansive smooth valleys were rimmed with tall mountains. The majestic granitic Sierras, light with snow cover rose, abruptly to the west from the valley floor. 

The Sierras from Owens Valley (Mt. Whitney is in there somewhere...)


The last day of our journey took us to Death Valley National Park and further south to the metropolitan expanse of southern California. Coming up towards the park, we saw Joshua tree sentinels on the landscape. We did not proceed deep into the park, but did drive through the Panamint Valley, an utterly barren swath of land set between the Argus Mountains to the west and the Panamint Range to the east. Though not hot on that late December day, one could easily imagine the searing heat of the landscape during the death days of summer.

Notes:

1. A concise history of Sierra geology.
2. Muir, J. 1911. My First Summer in the Sierra.
3. The road was finally closed on 17 Jan 2012. See the NPS data here.