Sunday, September 19, 2010
I just returned from a couple days up at Lyell and Maclure Glaciers with videographers Josh Helling and Steve Bumgardner and park geologist Greg Stock. Greg was checking some of his instrumentation on the glacier while Steve and Josh were working on an installment of the excellent Yosemite Nature Notes video series. I was on my annual survey trip to take the photographs that show the rate of recession of the ice.
There's been no debate about climate change in Yosemite for 150 years; even young John Muir knew that the park's glaciers were melting away. The first glacier that Muir explored is now gone and the Maclure is half the size it was when Muir conducted the first quantitative glacier measurements in North America. That reducing trend continues with the east lobe of Lyell Glacier having wasted away to a couple small flakes of ice on the cirque headwall, and the west lobe steadily shrinking year by year. Last winter's above average snowfall is still evident but isn't likely to sustain the glacier significantly. According to Greg, the western quarter of the west lobe is not quite a meter thick; a major areal reduction looms. The east edge of the west lobe has fallen 37 meters in elevation in the past 60 years.
For next summer I'm planning a Yosemite Conservancy trip to see Lyell, and a trek to where Muir found the first recognized glacier in the Sierra. Think about a visit to Yosemite's ice before it's gone...