Wednesday, October 21, 2015

Merced Nadir

Rain and snow over the weekend have brought the Valley's waterfalls back from the dead. Bridalveil, Staircase, Royal Arch, Snow Creek, and Yosemite Falls went from trickles or dry rock to photogenic surges overnight. On Sunday, some of us witnessed Mirror Lake going from dry sand basin to reflecting Mt. Watkins in a matter of moments as thousands of gallons per minute poured into the lakebed in a flash flood. There are six inches of new snow along parts of the Sierra crest.

The Merced River is typically at its lowest point for the year at the end of September. Until these rains, it was continuing to drop, running at about half its normal low flow. The river and waterfalls are dropping again now as the rainfall runs off; the Merced is very muddy due to erosion from steep areas that have burned in the past two seasons.

Despite catastrophic blazes elsewhere in California our fire season in the park was mild; several early July lightning fires crept slowly along the forest floor for months at healthy low intensity. A few human-caused fires were contained before they got too far. A good stretch of the Valley floor's south side continues to smolder from last week's prescribed ignition.

The San Francisco Chronicle featured Tom Stienstra's cover story about the disappearing Lyell Glacier last Sunday; the best version is online only for subscribers but you can see a PDF of the print edition here. It'll be interesting to see what sort of layer this El Nino winter brings to the glacier; even if it's huge, it'll only delay the terminal decline briefly. I look forward to bringing a group (or two) of very fit backpackers up there late next summer to have a look.

My summer was VERY busy with lots of good stuff (Lyell Glacier, Switzerland, Half Dome, etc.) but now I look forward to resuming more frequent posts here.