The Range of Light

Twilight Crescent, Mt. Whitney
Sony a7R II
Sony 70-200 f/4
1/3 second
F/11
ISO 160

“… the mighty Sierra, miles in height, and so gloriously colored and so radiant, it seemed not clothed with light but wholly composed of it, like the wall of some celestial city…. Then it seemed to me that the Sierra should be called, not the Nevada or Snowy Range, but the Range of Light.” — John Muir

Anyone who has spent time in or around the Sierra Nevada has to agree that there’s something special about its interaction with light. Towering one to two miles above the surrounding terrain for nearly all of its 400-mile length, the Sierra Nevada are California’s most prominent natural feature. But it’s not just prominence that sets the Sierra apart. The Sierra are almost entirely granite, an intrusive igneous rock comprised primarily of light-toned feldspar and liberally infused with lustrous quartz and mica. Because igneous intrusive rocks form deep beneath the Earth’s surface, constituent minerals cool and harden slowly enough for large, reflective crystals to form.

In addition to its inherently reflective qualities, granite is quite hard and resistant to erosion. Unlike the overlying sedimentary and metamorphic rock that washed downhill as the Sierra pushed (and continues to push) upward, granite remains intact when subjected to wind and rain. Eventually small cracks form; water percolating into these cracks expands as it freezes, widening the cracks further until the granite fractures and a large block separates. The result is large vertical and domed surfaces whose extreme slope and hardness are particularly inhospitable to plant life, even well below the timberline. Granite’s hardness also means that rather than crumbling beneath the weight of the numerous glaciers to scour the Sierra, much of the Sierra granite has been polished to a glassy sheen.

Granite’s light complexion, reflective inclusions, and abundance of exposed, polished surfaces make the Sierra particularly inclined to reflect the color of whatever light illuminates it. This relationship with light is quite evident in Yosemite Valley, nestled in the range’s more moderately sloped west side. When the sun strikes Yosemite’s Half Dome and El Capitan at day’s end, warm sunset light paints these monoliths in brilliant orange and red hues just before the sun is snuffed by the horizon. While this color can be seen at sunset year round, it takes center stage each February when sunset shadow and light conspire to highlight normally insignificant Horsetail Fall’s tumble down El Capitan’s east face.

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As exquisite as the light on Yosemite’s granite is, I’m even more drawn to the Sierra’s east side, which gets its best sun at sunrise. Unlike the Sierra’s gradually sloped, relatively moist, and largely foliated west slopes, the Sierra’s east side is much steeper, drier, and therefore sparsely foliated and more exposed. Enhancing the drama, the Eastern Sierra’s towering granite face also catches the earliest possible sunlight, sunlight that has traveled farther and through purer air (because there fewer airborne pollutants in the morning in general, and the sunlight east of the Sierra traverses much less densely populated terrain).

My favorite place to watch the light play on the Eastern Sierra granite is in and near the Alabama Hills, two vertical miles beneath Mt. Whitney and the Sierra’s most precipitous section. Looming above the Owens Valley, 14,505 foot Mt. Whitney is the highest point in the 48 contiguous United States. Unlike many towering peaks that stand by themselves, Mt. Whitney is bounded by 13,000 foot Lone Pine Peak and 14,000 foot Mt. Williamson, all connected by a serrated ridge of 13,000+ foot sharks tooth prominences.

Before sunrise I like to arrive early enough to see the Sierra crest reflect the pale blue of the pre-dawn sky, then watch it warm gradually as the sky brightened before the approaching sun. The color reaches a crescendo when the sun’s longest wavelengths first kiss the highest peaks with pink alpenglow. As the rest of the sun’s visible wavelengths join the party, the crest warms to amber before finally cooling beneath the daylight-blue sky.

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At the end of the day the best color arrives after the sun has long disappeared behind the crest and the entire scene is illuminated by a sky well on its way to night. Though the mountains’ color is more subtle than the sunrise show, the Eastern Sierra’s granite when imbued with the pale mauve of evening twilight is no less beautiful. Eventually night takes over and once again the Sierra granite throbs a soft blue.

Early last October I guided my Eastern Sierra workshop group up to Whitney Portal at the base of Mt. Whitney to photograph cascading Whitney Portal Fall in late afternoon shade. On the drive back down we squeezed into a small turnout not too far down the road for the closest view of Whitney that doesn’t require a serious hike. This year’s group got a bonus when a thin slice of brand new moon appeared shortly after sunset.

Mounting my Sony 70-200 f4 on my a7RII, I framed the scene as tightly as I could while still including both Mt. Whitney and the crescent moon. Though the sky was clear, a steady stream of small clouds materialized as if issued by a cloud making machine just out of sight behind the crest to the right of Whitney. Each new cloud scooted to the left and dissipated quickly in drier air near the summit. After composing, metering, and focusing, I waited for the next cloud to appear and clicked this frame in the purple twilight.