Re: SC80

http://www.theolympian.com/nationworld/story/636137.html

Yosemite glacier on thin ice

ON THE LYELL GLACIER – As melting water gushed off the ice in a tinseled maze of rivulets and tumbled through a gaping chasm, the hikers watched, wondered and worried.

Unlike most backcountry travelers who pitch their tents along the John Muir Trail in the upper reaches of the Lyell Fork of the Tuolumne River, these visitors had not pushed on to scale the summit of Mount Lyell - Yosemite's highest peak.

Instead, they scrambled up a ridge of rose-tinted granite and over a mound of dark, unstable boulders to tromp across this less well-known corner of the national park, a silvery-white sheet of ice fast becoming one of the first California landmarks to succumb to climate change.

Later in the day, Pete Devine, a veteran glacier observer who manages educational programs for the nonprofit Yosemite Association, sat on a log and opened a notebook. "Gaunt remnant of what I saw 10, 20 years ago," he wrote in his journal. "Lots of large boulders dot the surface. Lots of melt water flow."

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.