Sunday, October 26, 2008

Yosemite glacier on thin ice

The Olympian (Olympia, Washington) has a long story, full of detail:… As signals of climate change begin to come into focus in the Sierra Nevada, its melting glaciers spell trouble in bold font. Not only are they in-your-face barometers of global warming, they also reflect what scientists are beginning to uncover: that the Sierra snowpack - the source of 65 percent of California's water - is dwindling, too. More of the Sierra's precipitation is falling as rain instead of snow, studies show, and the snow that blankets the range in winter is running off earlier in the spring. And snow in the Sierra touches everything. Take it away and droughts deepen, ski areas go bust and fire seasons rage longer.

Some glaciers already have melted away, including the first Sierra glacier discovered in Yosemite by John Muir in 1871. Today, the remaining 100 or so are withering, including Lyell, the second-largest, which could be gone inside a century. "All across the Sierra, glaciers are transitioning into ice patches. Ice patches are transitioning to snow fields. And snow fields are transitioning into bedrock," said Greg Stock, a geologist with Yosemite National Park who joined Devine last month on an annual survey of the Lyell glacier….

Lyell Glacier is the largest remaining glacier in the Sierra Nevada mountains of California, National Park Service image

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