Physical Cliff

Our physical cliff is a combination of higher pitches and reduced horizontality...
A couple of inches of snow came to Yosemite Valley Wednesday night and it's staying on the ground, at least in the shady areas.
The skies are meant to be off and on cloudy/wet the next few days. This could make for a damp Christmas Bird Count this weekend, the 16th, but the birds aren't going anywhere so we'll count whatever we see. Contact our compiler at sarah_stock@nps.gov if you're interested in participating in this grand citizen science project. Yosemite's count has been tops in the nation more than once in recent years, for numbers of white-headed woodpeckers and Williamson's sapsuckers. We have superb woodpecker habitat in our diverse forests.

Light quantities of frazil ice have been observed flowing in Yosemite Creek the past couple of mornings. Overnight mist-ice accumulations on the wall of Upper Yosemite Fall has led to loud booms by mid-morning as huge flakes peel off in the sunshine and start accreting into the snowcone.
XC skiing at Badger Pass opens this weekend, on 12 inches of new snow. The slopes need a bit more depth, still. We've had plenty of storms but the snowline has been high, almost as if the climate were changing...

December Rains

Recent storms have ended our Indian Summer conditions here. The snowline remained high, and it's quite mild this week, but Glacier Point and Tioga Roads are closed to cars (probably until May).
The Merced River shot up from around 60 to just over 2000 cfs in Yosemite Valley during the latest wave of heavy precipitation. Our waterfalls have roared back to life after a long parched spell.

Leaves are off the deciduous trees now. At the same time, El Portal has a lush ground cover of brand new grass and forb growth. Newly sprouted lupines and cranesbill are already identifiable by their foliage, but we don't expect flowers for a few months.
I spent Saturday pursuing nothing but woodpeckers; we encountered six species between El Portal, Foresta and Crane Flat - a couple more hours of daylight might've turned up more of this interesting taxa. Acorn woodpeckers are very busy storing and sorting this year's crop. Did you know that they're in the same genus as the Lewis Woodpecker? The genus name Melanerpes translates as 'black creeper.'
The Conservancy's 2013 field institute courses are all now open for registration; you can find birding, wildflowers, geology, photography, family programs, art courses, backpack treks and no less than seven trips to Half Dome in the "Yosemite Outdoor Adventures" line-up. Yosemite has something to teach you...

Peak leaf-peeping weeks

-Foliage in Yosemite Valley is at its peak color now. While weekdays are very quiet, recent weekends have brought in lots of leaf-peeping visitors. Black oaks, big-leaf maples, and black cottonwoods are all shining in their various yellows. Dogwoods own the red/pink. The sugar maple is bare.
-Michael Frye reported seeing azaleas blooming in El Capitan Meadow, and sure enough, I found them yesterday. On many of these yellowed shrubs are fresh, bright white flowers. The fragrance isn't strong, but a sniff puts one right into the warm days of June.

-In the canyon below Yosemite Valley, there are miles of grapevine - invisible all summer - now declaring its presence with yellow leaves. It's truly remarkable how abundant wild grape is, now that it's highlighted.

-The Merced River is still running quite low, at about 60% of average volume. The storm that's arrived today is not expected to add much precipitation, though we should see a bit of snow at low elevations. We'll probably lose some of our colorful leaves, but that just makes walking through the fallen foliage more fun.
-Our final field seminar of the year is on December 1: "The Day of the Woodpecker." You'd be astounded what there is to know about Yosemite's diverse group of woodpeckers.
-We start 2013 programs with snowshoe treks, and two special photography courses. All leaves remaining through the winter will be green; come see.

Click or Treat

It's a great time for photography in Yosemite. Though the sugar maple has gone bare, the big-leaf maples, dogwood and dogbane are really bright now, if you're in the right places. Oaks and cottonwoods are waiting their turn in the Valley. The Crane Flat and Hetch Hetchy areas are really colorful now.
-Photographers Keith Walklet and Mike Osborne still have a few spaces in their November 1-4 field program with Yosemite Conservancy. They are a remarkable team with a lot of Yosemite accomplishments to their credit.

-Two dark bears were seen for several days eating acorns high in a valley oak by the railroad engine in El Portal. In Yosemite Valley, they've also been harvesting directly from the canopy. With bathing suit season over, the bears are trying to take in 20-30,000 calories/day so they'll have a comfortable winter's sleep.
-Winter birds have arrived: juncoes, white-crowned and golden-crowned sparrows have descended to find seeds in snow-free El Portal for the winter. Varied thrushes have been seen in the Valley and near Merced Grove already. Naturalist Dan W. reports a meadowlark in Ahwahnee Meadow from earlier this week, when he was leading a "Yosemite Insider Experience" group for the Conservancy.
-We had another mild storm come through Monday, closing Glacier Point and Tioga Road with a few inches of snow. They're both likely to re-open shortly. The precipitation finally initiated the river's seasonal rise, from the year's low of 18 up to 26 cfs. Normal would be in the low 30's.
-I had a chance to examine one of the hand-hewn wooden stakes that John Muir used 1872 for the first quantitative glacier study in the U.S. It was found by NPS personnel on the 1936 glacier survey and brought to the park's museum archive. It was pretty interesting to handle something that Muir himself made when he was up at our glaciers with Galen Clark and Joseph LeConte. Regretably, Muir didn't bring his digital camera on those two trips...

Insatiable albedo

It's autumn and in Yosemite Valley:
-days are shorter
-the cliffs and trees cast longer shadows
-the sun is at a lower angle so it lights less ground
But we also find that:
-the lower sun lights the north wall more directly
-the pale, dry grass gives off a brightness not seen in summer's dark green
-the yellow of maples, milkweed, dogbane, raspberry and some oaks and cottonwoods add increased reflectivity to the substrate, from leaves both on plants and that have fallen on the dark ground.

This 'yellow day of October' bears out Muir's notion that the Sierra may actually be composed of light. It's nice to contemplate the conflation of matter and the electromagnetic spectrum while beholding the reflected glow with your own eyes here in Yosemite.

-In the Valley last week Conservancy naturalist MRoss observed both a gray catbird and the Asiatic form of an American Pipit.
-The one sugar maple in Old Yosemite Village is bright red-orange now.
-We are getting our first dusting of snow in the high country, with Tioga Pass being closed briefly.
-The Merced River flow at Pohono Bridge has flatlined at a thin 19 cfs. The historical average river volume for today is 30 cfs and rising.
-Geologist GStock's latest glacier observations indicate a rate of motion for the Maclure Glacier that is identical to what Muir measured 140 years ago. Sadly, though it's bigger than the Maclure, the Lyell Glacier appears to be in a terminal phase.
-That's Venus you see, really bright in the eastern sky in the morning. The nearby star is Regulus, the brightest star of Leo. What can we interpret from the apparent proximity of the goddess of love and the king of the beasts? Only our own spatial provincialism; Regulus is not close but is 77 light-years away from Venus. Regardless, the light of both bodies adds to the shine of not just Yosemite, but our whole bright world.

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.

Heat and monsoon

It's been really hot in Yosemite for the past week, with Yosemite Valley temperatures in the high 90's (but only the high 30's for European visitors...)
While it feels like El Portal could just burst into flame at any moment (it's been up to 110 degrees) the park has been having a surprisingly light fire season to date. The Cascade Fire, east of Crane Flat has been burning quietly for two months now and is still not quite 700 acres. There's a small lightning-caused fire at the top of Vernal Fall and another tiny blaze near Porcupine Flat.
Monsoon moisture that's come in with the heat has made for great cloud shows ("higher Sierras" in Muir's words) recently. You can partake via webcam without threat of hail or lightning. The Merced River has actually doubled in volume in Yosemite, right up to a normal/average flow, because of the upstream rains. A bit of rain fell in Yosemite Valley and west yesterday afternoon - what a pleasant change.
We look forward to the southward migration of birds of prey over the next several weeks. Michael Ross will lead a field seminar on September 8 for those who want to observe this annual phenomenon in the high country.

Raccoon Days

Dry 'raccoon days' of July have baked Yosemite. August's 'Dog Days' were named in ancient times when the Dog Star (Sirius, the brightest star in the constellation Canis Major -the big dog) became visible just before sunup. Though we can't see it yet in our deep canyon, this bright star is already rising earlier and earlier before the sun.
Before Canis Major and Sirius rise, the Little Dog, Canis Minor comes up from the east. The bright star in Canis Minor is called Procyon. This is also the genus name of the raccoon. The German taxonomist who gave our raccoon its Latin name in 1780 assigned this animal a ranking slightly preceeding dogs; Procyon means 'before the dog' and this also works with this star rising before Sirius. Therefore, perhaps we can stretch the astronomical story to say that Raccoon Days come before Dog Days. Learn more about the stars in our 10-11 August Tuolumne astronomy program.
As far as terrestrial wildlife, up until recently bears have been relatively well behaved this season; there have been fewer car break-ins than usual.
The Merced River continues to flow about 20% of normal volume. It could keep dropping for two more months but it's already less than half the flow of last year's lowest volume. The photo shows Bridalveil Fall in a wispy state this week.
We have one very modest fire burning in the park. It's near the headwaters of Cascade Creek, just south of Tioga Road and east of Tamarack Flat. Lightning started it in mid-June and it's grown to less than 150 acres over 7 weeks - seems almost as though fire just fits in here...

Interdependence Day

Sierra summer is at its finest now. Heat and blue skies make up our days, the waterfalls shrink, birds quiet down as they taper off feeding young that are fending for themselves, bears with cubs explore opportunities for their own kinds of Yosemite picnics. A little smoke in the air would complete the feel of the season.

The Merced River flows at just over 100 cfs in the Valley - normal for this date is over 600 cfs; a dry winter makes a dry summer and Yosemite Falls is a dwindling presence.
I was up at Summit Meadow along the Glacier Point Road this morning and had that pretty part of the park to myself for a while. Shooting stars, bistort and Bigelow's sneezeweed (yes, that's a fun name to say) are profuse now. Yellow-rumped warbler, Steller's jay, and a Townsend's solitaire added an aural dimension, but the voice of the hermit thrush coming from the dark fir forest is like nothing else in the Sierra. New fencing between the road and the meadow should help protect this sensitive spot.
From the far side of the world: Yosemite's Chinese sister national park, Juizhaigou, reports finding the first fresh panda scat in the park in over ten years. Giant pandas depend on bamboo which blooms, dies off and becomes unavailable for years at a time on a localized basis. Juizhaigou's bamboo has regrown to make it perfect panda habitat again. Perhaps the Conservancy may be taking another group of Yosemite-philes to hike in our two sister parks in China next fall.
Speaking of excitement, we are delighted that legendary Ranger Dick Ewart is leading two Yosemite Outdoor Adventures for people this summer: a 5-day trek from Tuolumne Meadows for experienced backpackers, and an off-trail dayhike to the top of Tenaya Peak. These are special opportunities to experience some of what makes Yosemite such a great place.

Solstice Dreams

Yesterday was our longest day for enjoying Yosemite. A thin trace of smoke from the 234-acre controlled burn near Hodgdon Meadow added dimension to the Valley skies - surely a sign that it's summer.
The Merced River would normally be flowing at over 1400 cfs at Pohono Bridge on this date; today is just over 200 cfs. Yosemite Falls is light, but still photo-worthy; it won't be in a few weeks, and it'll completely disappear in August. Mirror Lake still has water in it -as well as people in it, enjoying the gentle flow for cooling off.

Draperia, Azalea and Spicebush bloom in the Valley. Tanagers and both vireos are still singing; grosbeaks are quieter. Saw Vaux's swift over the Visitor Center yesterday. The Conservancy was a sponsor of last weekend's successful Mono Lake Bird Chautauqua - lots of birds and even more great birders.
The museum has a new exhibit in the gallery: historic landscapes that include Ayers, Moran, Jorgensen, Beirstadt and Obata. It's there to the end of September.
There was a 2.4 earthquake 16 miles beneath Crane Flat on Monday afternoon - an unusual place for this, but the Sierra is very much a living range.
Visitation has been busy but not as busy as last year when lots of media attention to above average waterfall flows drew extra crowds early in the summer.

The Conservancy has a wonderful art course coming up in mid-July: "Tuolumne Meadows Pastels" with Moira Donohoe. It's a great chance to improve some skills in a remarkable landscape.

Summer is On

Memorial Day weekend started with snow and road closures.

The holiday weekend featured the predictable crowded roads and difficult parking in Yosemite Valley and at Glacier Point. It's been an interesting experiment to try separate lanes for cars and buses in the east end of the Valley. I was camped near a quiet meadow where I saw no one, but a bear and a great grey owl. Such is Yosemite.

El Portal was in the mid-nineties all week, all grass and forbs are brown. The Merced River is running at 25-30% of average volume. The waterfalls are shrinking noticeably. Sentinel and Ribbon Creeks barely trickle to the river now, Woski Pond is down to about 30' at its widest point.

Birds and flowers are still plenty active. Two vireos, grosbeak, tanager, a few warblers, 2-3 flycatchers, and the hermit thrush are heard as you get up above the Valley. Seems like we've been seeing more Vaux's swifts in the Valley this season. Azalea is perfuming Valley meadows now, cow parsnip is opening. Dogwoods fade, but are still nice higher up. Noticed a monarch in the Valley this morning, as milkweeds are just starting to open. Pale swallowtails are abundant this year.

Tuolumne Meadows hosts artist Moira Donohoe in a pastels workshop in mid-July; should be nice time to get beauty on to paper with her there.

Farewell to Spring

Despite recent warmth, the Merced River has started to decline in volume already; it's running just below average (while the average is still ascending). We are excited to have our new webcam up, showing you Upper Yosemite Falls so you can keep visual tabs on the flows. We expect that by September this year it'll just be the 'Yosemite Wall' webcam.
Indian, Sentinel, Royal Arch and Ribbon Creeks all still run to the river. Eagle Creek has shrunk back from Northside Drive.
The high country along Tioga Road still has snow, lots of soggy trails, no new greenery - it's too early for dry, comfortable hiking that won't leave considerable impacts. People tend to hike outside wet trailbeds, creating new trails and crushing plants as they're trying to get started. Things will be drier in June and it'll be easier to LNT.
Yosemite Valley is alive with birdsong; yesterday's birdwalk included black-headed grosbeaks (plentiful and loud), western tanager, yellow, yellow-rumped, and black-throated gray warblers, Cassin's vireo, white-throated swift, flicker, oriole, Anna's hummingbird displaying in front of the Visitor Center, and more.
In the El Portal area the Clarkia (Farewell-to-Spring) is in bloom, as is buckeye, Ceanothus, and elderberry. Most of the grass and forbs have gone to seed and are browning. The dogwoods in the Valley are glorious right now.
Check out the eclipse of the sun on Sunday at sunset. We were not sure that Yosemite would be a good place from which to observe this spectacle because good western views from places like the Glacier Point Road might not yet be accessible; this year they are. Crane Flat Fire Lookout and Sentinel Dome will be prime spots.
For more enjoyment of the earth sciences: there's still space in our one-day geology course on June 16. Park geologist Greg Stock is a marvelous communicator and will clarify all those questions you have about Yosemite's origins.

Arrivals

This morning's birdwalk in the Valley had so-so sightings of the bright triumverate of western tanager, black-headed grosbeak and Bullock's oriole. All of these, and the warbling vireos sang loudly in several places. Two species of swift were a nice plus, though we didn't see them well either. The small birds can't be happy that park biologist CB has identified 11 peregrine falcon pairs this season, with 8 known nests. Seven of these are along the Merced corridor between Arch Rock and Little Yosemite. Hungry baby predators will be hatching from eggs very soon, making our peaceful park a rough neighborhood for prey species. The river has dropped a bit since last week's rain; it's possible that it reached this year's peak on the 26th-about a month early. Meanwhile north-draining Sentinel Creek is now flowing in more channels. Indian Creek now flows beneath the Yosemite Art Center. This weekend afforded one of Yosemite's transient delights for visitors: bicycling on Tioga Road without cars. Several dozen cyclists rode the quiet corridor, from both east and west sides, with a good number rendezvous-ing at Olmsted Point. The marmots are standing by to pose for pictures there. Road crews are still working but it shouldn't be long until the pass is open to cars.

It has Sprung

Apologies for the long silence here at a time when so much is happening with the change of seasons in the Sierra.
We had a couple of decent snowstorms last week, now it's very warm.
The Merced River has finally gone to above average volume (at about 1700 cfs overnight at Pohono Bridge) and Table Rock is partly under. Waterfalls are looking quite good. Sentinel, Royal Arch, Eagle and Ribbon Creeks are all flowing into the river. Horsetail trickles into Wosky Pond.
Because our snowpack has less than half of average water content, we don't expect a high runoff this year - very different than last spring. The big melting this week suggests an early peak, too.
Our regular Monday and Thursday birdwalks in Yosemite Valley have turned up lots of singing yellow-rumps and the R2-D2 songs of orioles. Black-throated gray warblers are in, as are black-headed grosbeaks. We haven't seen flycatchers (other than black phoebes) or vireos yet in the Valley, though we know they're nearby.
Flowers in the Merced River Canyon west of the park have been dazzling for the past few weeks: poppies, redbud, birds-eye gilia, caterpillar flower, wallflower, false goldfields, popcorn flower, fiddleneck, cranesbill and dozens of others are still putting on a marvelous show. Buckeyes are green, and the live and deciduous oaks are adding new foliage and dangling their flowers.
Conditions look to be perfect for Dave Wyman's "Spring Light Photography" course, May 17-20. There are a few spot still available; free park entry and free camping are included.
As if we needed one more sign that spring has sprung: Glacier Point Road opens this weekend.

Vernal Equinox

Equinox arrives next week, when day length matches nighttime. Though they were closest on Monday night, it's still worth getting out in the evening to see the close positioning of Venus and Jupiter. They're a bright pair, impossible to miss as long as you have a view to the west for an hour or two after sunset. (You can actually see Venus with the naked eye all day, too, if you know where to look in the blue sky.) Though smaller than Jupiter, Venus is the more brilliant because it is closer to Earth.
Light precipitation off/on in Yosemite this week, with snow level remaining above the rim so far. We expect snow on the Valley floor this weekend. In the Merced Canyon below the park boundary, greenery is soaking up the moisture; great numbers of flowers are in bloom. Dense poppies cover the south-facing slopes in the area burned by the Telegraph Fire of 2 years ago. In contrast, last summer's Motor Fire area is generally not greening up well. Buckeyes are leafing out, elderberry leaves are barely emerging, and redbuds are just starting to show.
The waterfalls are below average in volume now, but it's good that we're adding some fuel this week for later runoff.
Contractors lucked out with dry weather and have re-opened the Big Oak Flat Road (connecting Yosemite Valley to Hwy. 120).
Superintendent Neubacher is contemplating adding more sister national parks - one on every continent is a goal. Asia and South America are already covered. We like the idea of Yosemite having this measure of global significance and await news of coming partnerships (and opportunities for travel to visit new relations.)

Poppies and Teddy

The Merced River canyon below the park boundary has an early abundance of wildflowers including slopes covered with poppies in places. We've had a few modest storms over the past couple of weeks, adding a bit of snow above 5000 feet. The wet has brought out fiddlenecks, cranesbill, popcorn flower, baby blue eyes, paintbrush, red maids, etc. I haven't been up the South Fork but I bet it's getting colorful.
Chorus frogs are singing in various places, California ground squirrels are emerging in some spots, a turkey vulture was seen in the Valley this week. In El Portal, flickers and titmice have been 'singing.'
While spring tiptoes in at low elevations, we had a bit of frazil ice in Yosemite Creek this week, too.
The park has a new official place name: Roosevelt Point. This is on the south rim of Yosemite Valley, just west of Sentinel Dome, near the top of Sentinel Falls. Some scholars believe that Muir and Roosevelt camped near here on the second night of their 1903 trip together. They're usually described as having camped at Glacier Point because that's a better known landmark than the forest near Sentinel Dome, and because of the famous photo-portrait of the two men at Glacier Point. Sentinel Creek would've been the most reliable water source for a camp, so it's likely that they actually spent the night there.
TR will be coming to Yosemite Conservancy's Spring Forum on March 31 in the form of actor Alan Sutterfield. He and John Muir (Lee Stetson) will chat about their time together and their passion for park stewardship. Muir visits us again on John Muir Day, April 21, this time in the person of actor Frank Helling. He'll be strolling with Muir's great-great grandson, Robert Hanna for one of the Conservancy's field seminars.
We pursue Muir's footsteps again in July, backpacking on a field seminar to where he recognized the first known glacier in the Sierra. Climate change (as even Muir realized back then) has removed all but relictual evidence of the glacier's presence. We visit a living glacier in August's field seminar trek to the north slopes of Mt. Lyell.
History lives on.

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.