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.

Fall or Winter

It's a mild week in Yosemite but most trees are bare and there's morning frost in Yosemite Valley. Tioga Pass is open to cars but Glacier Point Road is closed. A Clark's Nutcracker drifted down from treeline and was heard above the Valley's west end, while aerial plankton of spiders and small insects fills the air in the afternoon sun.
Balloon flies continue to float in quantities in El Portal, where Grindella is still in bloom. Juncoes and mixed winter flocks have displaced the swifts and swallows of summer. Fresh bear tracks were seen in the snow at 7000' on Thanksgiving day.
I was just outside the park with friends yesterday and saw 4 river otters on the Tuolumne River. Park biologist SStock has records of 37 prior sightings of river otters in/near the park. They include observations from throughout Yosemite, including up to 10,000'. Has fish introduction allowed the otters to range higher or stay longer than pre-fish?
This weekend is the Conservancy's woodpeckers field course; we have more kinds of woodpeckers than almost anywhere. Good weather should make a pleasant day for a quest to see as many as we can while learning about this important keystone guild. Our Christmas Bird Count is December 18 and would welcome more participants, whether experienced birders or not. Maybe mild weather will last, though La Nina is expected to be visiting for the winter.

So Autumn

The fall glow in the Range of Light is especially remarkable in Yosemite Valley these days. We are at that point in the sun's apparent migration in the sky when it sets very low in the west, in the skyline notch that is the Merced River Canyon. It's the analog sunset point to that which produces the 'firefall effect' at Horsetail Fall. That photogenic phenomenon happens about 7-8 weeks after Winter Solstice; we are now 7-8 weeks before solstice. The low sunset lets a more colorful sunlight into the Valley at the end of the day. (Horsetail Fall is just trickling now so won't produce the volume of mist/water that catches the light in February.)
In mid-summer the sun sets well to the north of the Merced's exit point, so is high over the canyon rim; in winter it sets high over the canyon wall to the south - in both cases setting when the sunlight is still whiter.
During the day, the sun is traversing a lower angle than in summer, too, but still reaches more of the Valley floor than it does in mid-winter. The Valley's deciduous plants are ending their growing season with the decay of chorophyll that allows other leaf pigments to shine before leaves drop to the ground. Big-leaf maples put on the biggest color display now, and these bands of yellow highlight their preferred wetter, shady habitat in ways that may not have been apparent all summer. The one sugar maple in Old Yosemite Village turned more yellow than red this year, and the afternoon up-canyon breezes have this tree already about 20% bare now. Black oaks are going brown-yellow but many leaves have dropped from some. Dogwoods are still largely green, but showing their startling pink in places. Black cottonwoods are mostly bare now. The brightest plant in the Valley now is dogbane or Indian hemp (Apocynum) - their radiant gold almost hurts one's eyes.
The meadows are a light brown, the fallen pale leaves cover darker ground, more sunshine reaches the ground through branches that are baring. Even ponderosas participate in this season, browning and shedding some of their needles after the dry summer. It all adds up to a lighter albedo. Though the days are shorter and the sun is lower, Yosemite Valley is reflecting more light and is brighter than it is all summer. Only the winter snow will raise the Valley's albedo beyond this dreamy, pale glow of autumn.
Incense cedars are raining their helicopter seeds now. Gray squirrels have been shredding pine cones for a few weeks and their litter of cone scales is everywhere. Been seeing more chickarees than usual in the Valley, also working over the ponderosa cones. Down canyon a bit, Torreya has been dropping its strange green fruits.
The Merced is running at about 80 cfs at Pohono Bridge and dropping since our last storm on 5 October (average for this date is around 33 cfs). Last evening the Valley rim was entirely mantled in a cloud layer that built just at sunset.