Home A - Z FAQ Art Prints Online Library Discussion Forum Muir Weather Maps About Search
Online Library: Title Author California Geology History Indians Muir Mountaineering Nature Management

Next: Mystery of HydromantesContentsPrevious: Enid Michael

Yosemite Nature Notes 46(2) (1977)


Yosemite Falls lightning close
[click to enlarge]

Yosemite Falls lightning
[click to enlarge]

Lightning and The Landscape

by William T. Wiley

Folklore has it that lightning never strikes twice in the same place. If you have ever traveled an exposed ridge and studied the tops of the larger trees, or watched a lightning storm cross a high country lake, then you know that folklore isn’t always true.

One of Yosemite’s most recent, and most noticeable, examples of lightning’s force can be seen close to the west edge of Upper Yosemite Fall. A 250' flake of rock has been peeled off this massive granite surface, to expose the original color and texture of that portion of the Sierra’s skeleton. The surrounding rock still is covered by a layer of living lichens which, growing slowly, will take many years to cover the newly exposed surface.

Most Park visitors do not notice the rockslide, and those who do probably conclude it to be a normal part of the weathering process caused by ice expansion between the layers of the rock. Some may think it an “intrusive” rock formation, formed when the granite heart of the Sierra, cooled from molten materials, was forced from the earth’s core below. Some imaginative visitors have suggested that “it’s painted,” or “it’s covering some enormous four-letter word”. Only a few seem to recall the sheer wall as it was, before the great flake was split off. Its removal marks the release of one of nature’s most unpredictable and sometimes frightening forces.

The first to notice its passing detected something “odd” about the way the Falls looked one Monday morning. Some took photos to compare with others they had of its former appearance. Few had heard the thunderous crash, and fewer knew the real story, that a huge flake of granite had been dislodged by a bolt of lightning. One observer was riding a Valley shuttle bus at a time when most visitors had taken shelter from the weather. As he watched, he must have felt somewhat as the Indians might have when they witnessed the heavens unleashing their fearsome might: a humbling respect for the variety of forces which shape the Yosemite environment.



Next: Mystery of HydromantesContentsPrevious: Enid Michael

Home A - Z FAQ Art Prints Online Library Discussion Forum Muir Weather Maps About Search
Online Library: Title Author California Geology History Indians Muir Mountaineering Nature Management

http://www.yosemite.ca.us/library/yosemite_nature_notes/46/2/lightning.html