Equinox Arrives

Yosemite's weather is still quite warm, but is hinting at autumn. Though mild this week, there has been more frost in high elevation meadows and the bilberry is reddening.
-At the foothill edge of the park, redbud leaves are yellowing and poison oak is going bare. Higher up, dogbane and the green Ceanothus are both going yellow. No color yet in maples, cottonwoods or oaks in Yosemite Valley.
-An osprey has been seen regularly in the El Portal stretch of the Merced for about the past month. The river is running only 23 CFS at Pohono Bridge meaning fish have fewer places to hide. Naturalist Michael R. saw pintails in Tuolumne Meadows last week.

-We've all learned a lot about the epidemiology of the Sin Nombre Virus (Hanta) and about the reactions of people to unfamiliar threats in the past few weeks. It's a most regretable situation.
-The park geologist has measured surface velocities in the Maclure Glacier and the West Lobe of the Lyell Glacier. Though shrinking quickly, both are still living glaciers. The Lyell is moving so slowly that it may grind to a halt in just the next few years; while the surface is still sliding downslope it's possible that the base is already static on the bedrock.
-Though we had such a dry winter, we've only had one real fire this summer: the Cascade Fire, started by lightning in mid-June, just south of Tioga Road between Crane Flat and White Wolf. In 3 months of creeping along the ground it has burned only 1200 acres.
The park's Fire Ecologist Gus Smith will be leading an exploration of the Mariposa Grove on Friday 28 September. This program is open to the public and is sponsored by Yosemite Conservancy. As with all Yosemite Outdoor Adventures courses there is free park entry and free camping.
-Also burning are the stars of Orion in the east before dawn, creeping their way higher into the approaching night skies of winter.