Darwin in Yosemite

"His noble character has suffered from silly, ignorant, and unbelieving men who say much about Darwinism without really knowing anything about it. A more devout and indefatigable seeker after truth than Darwin never lived." -John Muir, 1878.
This Sunday is Charles Darwin's birthday. Muir read and was a fan of Darwin. For context: "On the Origin of Species" came out when Muir was 21 years old (still living with his family in Wisconsin) and 5 years before Yosemite was first protected (with the signature of President Lincoln, who was born the same day that Darwin was!) Muir's writings made it into print while Darwin was still alive, but it's doubtful the British naturalist encountered the Sierra naturalist's tales. These two great individuals are closely joined in perpetuity south of Yosemite where Muir Pass provides access to Evolution Basin and the John Muir Trail runs beneath Mt. Darwin.
Our dry spell continues. We had a day of light drizzle on Tuesday. A few chorus frogs are calling at lower elevation, but they sound parched. Another chance at precipitation comes through on Sunday/Monday. NPS snow surveys show around 30% of average water content for our park watersheds. Elevations below the survey areas are drier yet. The Merced is flowing at 60% of average now. A few common mergansers have been paddling in El Portal, dippers doing a bit of singing.
On Saturday 10 March one of the park's best (and most delightful) naturalists, Karen Amstutz, is leading a fun Conservancy field seminar on snowshoes from Badger Pass out to Dewey Point and back. If you're up for a modestly physical (and extremely pleasant) day of exploration and discovery, think about coming up to join Karen. If you love a Yosemite experience, this one's a natural selection.

Rock and Road

I had a chance to explore the area of the 22 January rockslide on the Big Oak Flat Road recently. The slide is maybe a couple hundred meters west of the old diversion dam at the junction of 140 and the Big Oak Flat Road (sometimes mistakenly called Hwy. 120 here). The rockfall happened in the middle of the night, after a couple of rainy days. It originated perhaps 5-600 feet above the highway, dropping straight down a cliff face onto the talus above the road. It broke through the roadbed of the Big Oak Flat Road and NPS road crews did well to rebuild it so quickly; their patch should be repaved soon. The material that came loose totals about 500 cubic meters and is dominated by one large boulder half the size of the Yosemite Conservancy office building in El Portal. It cut a very straight swath through the mature live oaks and bay trees above and below the highway, not spreading out too much.
Surprisingly, the big rocks rolled to a stop about halfway between the Big Oak Flat Road and Highway 140, still on steep enough terrain that it seems they might have spilled to the river. One refrigerator-sized slab did make it all the way to 140 but it stopped in the storm drain ditch on the side of the road where almost no one would notice it. Some bigger rocks came within 10-20' of reaching 140.
A couple of jumbo SUV-sized boulders were stopped by a historic artifact: the old penstock foundation. This is a rock causeway built 1916-18 that supported the redwood pipe which carried water almost a mile from the diversion dam to plunge down through the turbines of the powerhouse at Cascades. It's interesting to think that the Valley used to generate its own carbon-free electricity from the Merced. Two weeks ago part of that relict operation caught a couple of big rocks (pictured) that might have smashed Hwy. 140 - an energy project that captured a rockfall's energy. (The one really big boulder stopped immediately above the causeway, slowed by the irregularities of its shape and the slope down which it tumbled.)

Hint of Winter

It's been both a challenging and a welcome return to stormy winter weather over the past several days in Yosemite. Tioga, Glacier Point and Mariposa Grove Roads closed last week, we got rain and snow, and the waterfalls picked up in volume. It snowed a couple of inches in Yosemite Valley yesterday, then clearing sky and swirling clouds at sunset made magic.
Ranger Ryan Hiller was killed by a treefall during the rain and high winds over the weekend. Ryan spent much of last summer patrolling the busy Half Dome trail corridor and was planning to work at our ski area this winter. He was the 10th known person in park history to perish in this manner and his loss is deeply felt by all of us here.
On Sunday night a section of the north canyon wall above the Big Oak Flat Road came loose and wrecked part of that highway between the Merced River and the Foresta turn-off. The slide is below the 3 tunnels, includes a lot of smashed live oaks and some very big boulders. Moving the debris is one thing, but the roadbed itself has been broken through and pushed downhill. NPS has posted pictures on their Facebook site. I'd guess that this will take at least a few weeks to reopen. There is some Sherwin glacial till in that area but this slide looks like all talus and cliff material.
Badger Pass got about a foot of snow and groomers have been working on the slopes. Warm weather the rest of this week will not help retain this base, but -you hear it here first: all Badger Pass operations will open on Thursday.
UPDATE: The Big Oak Flat Road reopens Saturday 28 January! Amazing work by NPS Roads to make this repair. Caution: unpaved gravel surface in the slide area.

Finally wet

After being dry for nearly two months we have a series of storms coming through Yosemite. Light precipitation overnight left snow down below 7000' in places. More accumulation is expected over the next few days, perhaps as much as 2-3 feet at high elevations by Monday.
Tioga Road is closed. Glacier Point Road is closed. But the snow level is high enough that we don't have any chain restrictions in effect. Badger Pass, at 7200' has a ways to go before even cross-country skiing will be possible there.
The Merced River had gone down to 27 cfs at Pohono Bridge - a mere 20% of normal flow! The tiny bit of overnight rain is showing up in the river already with a slight rise. Last night was quite a bit warmer than usual due to the cloud cover that limited radiational cooling. Some of the many frozen waterfalls that have been so visible for the past few weeks are softening up in the warmth and rain.
While Tioga was open, park resources people made some sound recordings of the lake ice on Tenaya, Dog and Lower Cathedral Lakes. If you were up there, you know how eerie those creaking, groaning, pinging sounds were. I hope they'll have some of these unique recordings available online soon.
Meanwhile the dry landscape is soaking up liquid moisture and stacking up the solid form for later use...

Wither Winter?

I saw a huge scorpion this morning. It was creeping slowly up into the southeastern sky just before dawn: Scorpio, a hint of distant summer. Vega was well up in the northeast- part of the Summer Triangle asterism. It's too close to solstice for these to really be harbingers, but (depending on your horizon; our irregular canyon walls can interfere with the trajectory of change) the sun is rising a bit earlier and setting later than it was a couple weeks ago. Mars and Saturn are also overhead before sunup; Jupiter and Venus after sunset.

The remarkable dry and mild season continues in Yosemite. January snow surveys show a fraction of normal snowpack (13% in the central Sierra) with some sample sites bone dry. Tioga Pass and Glacier Point Roads remain open. It is not true that our ski area is changing its name to "Badger Grass" (photo). While many have observed that this is the latest that Tioga Road has stayed open, others have wondered if instead it's actually the earliest (for next summer) that it's been open to vehicles...
The original road to Tioga Pass was built by hundreds of Chinese laborers. Some of the story of the contributions of non-Anglos to Yosemite is told in this new NPS video. I'm delighted with ranger Chan's research that brings to light more of the details of Yosemite's culturally diverse heritage (and future).
Western Bluebirds are seen at Crane Flat (99% snow-free at 6200'). Great horned owls are calling every night in El Portal, Foresta and the Valley. Chorus frogs are heard here and there, but only individually so far. The Merced River trickles at about 35% of normal flow.

Sierra Sin Nevada

Yosemite does not notice as people replace old calendars with new ones today; there is no date on the park's schedule. It's only our transient culture that has the conceit that we've just entered something called 2012 this morning. Solstice, a week and a half ago, is a more significant transitional event for our mountains.
Our December was one of the driest on record. There are a few inches of snow in shady places, but Tioga Road and Glacier Point Road are both dry and open to vehicles. Being able to drive to Tuolumne Meadows and over Tioga Pass is most unusual for Christmas and New Year's.
Visitors have been very excited to ice skate on Tenaya (pictured), Tioga and Ellery Lakes, as well as those wilder lakes requiring a short hike. XC skiers are hiking in to stay at Ostrander Ski Hut but without skis. In Yosemite Valley, people are comfortable in shirt sleeves mid-day; it should be in the mid-50's this week.
The Merced River has continued to shrink in volume, during the time of year when it's typically rising. At Pohono Bridge the average for today is 102 cfs, but it's now flowing at 38 - the lowest its been since October of 2010. (1977 was drier; only 14 cfs trickled through on January 1.)
The Christmas Bird Count recorded a healthy 70 species, including both species of eagles and lots of other raptors. It's a good winter for varied thrushes here and our white-headed woodpecker sightings will again be at/near the most in the nation.

Aeolian transition

As did much of the West, Yosemite had a strong windstorm last week. The park had closed the Tioga Road in anticipation of problems and there were indeed numerous lodgepoles felled in the area near the Mono/Parker Pass trailhead (almost at treeline) and a few elsewhere. In Yosemite Valley there were some trees thrown down and many branches flung on Wednesday night. The last of the deciduous leaves were stripped off, though the Cascades area must've been a calmer pocket as there is still color there.
Along the FourMile Trail several large trees were knocked down (photo).
For the first time in many months the Merced River has dropped to below average flow and is as low as it's been in 14 months.
Six species of woodpeckers were observed by my birding group on Saturday, and a seventh just after we split up. Now we await the snows and look forward to getting out in the winter world.
Get up early on Saturday morning to find a spot where you have a good view of a low western horizon. The earth's shadow will eclipse the full moon as the moon sets; you should see it turn reddish-orange as the sky brightens to day.