Tuesday, September 21, 2010

Equinox Report

We are half-way between solstices now. Sunlight shines on the park's peaks and canyon rims just before 7 a.m. It's frosty above 6000' in the low meadows at dawn. At Tuolumne and above bilberry is red, willows are yellowing. Smoke from the Slope Fire near White Wolf has tapered off. The Merced is down to 36 cfs at Pohono Bridge (still a tad above average). Fewer people are dipping in the river, but the Valley is still somewhat busy. Lessingia is the main flower still seen in Yosemite Valley. The famed sugar maple is still all green, but we see color starting in some dogwoods, bracken, sedges, and dogbane. Birds are quiet; year-round residents are mostly all that's left: raven, jay, chickadee.
I will be watching birds, etc. on the Conservancy's trip to Yosemite's two sister national parks in China for the next two weeks. I'll post from there if I can; otherwise it'll be towards mid-October for Yosemite updates.

Sunday, September 19, 2010

Lyell Glacier

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...

Friday, September 3, 2010

Labor Day in Yosemite

Park roads were very mellow before 9 this morning, but it'll be extra busy this afternoon and evening as visitors pour in for the long weekend. Good weather is expected.
It's warmed back up to "hot" now, after a cool spell last weekend which brought a few snowflakes to Tuolumne Meadows.
Datura still has some huge white blooms in El Portal, and gumplant is still yellow. There's still Madea in bloom at Cascades. Gin Flat, up at 7000' has lots of Solidago, Eriogonum, Yampah, Gayophytum, broad-leafed lupine in bloom - an exceptional flower season continues into September. Chinquapin is emitting its odd, musky odor now. If you haven't smelled this strange essence, now's the time for sniffing around at 6-7000'.
Leaves starting to turn color in the lower canyon now: spicebush, poison oak, grape, and redbud. Buckeye has long gone rusty brown.