Friday, May 18, 2018

Wet Spring

After another very dry winter, Yosemite has had a bit of recovery with a wet spring. We had warm storms in March and April and are now enjoying a string of about 10 days of cool, cloudy afternoons. The first weekend of April we had the markedly unusual experience of a very late, warm, winter-scale storm. This atmospheric river brought high elevation rain instead of snow, a flood forecast, and a successful pre-emptive evacuation of Yosemite Valley. Sure enough, the Merced River came up through the campgrounds, over the roads, through Housekeeping Camp, and filled the meadows. NPS has nice footage online. There's a persistent myth that these 'Pineapple Express' storms melt a lot of snow, but they really don't. It's the high elevation rain over thousands of acres of bare rock and thin soils that fills the river. This flood event wasn't from a 'monster' rainstorm, just a pretty big storm up high. Lower elevation side streams barely rose, compared to what the river did.

Because of the poor winter and the late-season rains, our springtime runoff peaked a month ahead of normal. The Merced and the waterfalls are already declining in volume, especially with the cloudy conditions we've been having. The clouds are delaying our minimal runoff a bit, which will help waterfalls last and forests to stay watered a bit further into the summer.

The park is still busy felling hazard trees, the small portion of our dead trees that might fall on people/roads/infrastructure. This year's below-average precipitation and above-average warmth will continue to stress Sierra forests (over-thick with trees due to decades of fire suppression) and we'll see more of the weak trees succumb to native bark beetles. Despite changes in Washington, D.C., the NPS in Yosemite is sticking with science and is not dodging the reality of climate change in its training of new rangers. The climate IS changing, it's changing NOW, in ways more rapid than ever, it is because of OUR hydrocarbon use, and it'll have serious consequences for US. It's disappointing that some political leaders think they know more than NASA or the National Academies of Science. Among other things, our fire season is longer, more severe and is costing us all more money to deal with. I'll be heading up to Lyell and Maclure Glaciers with Yosemite Conservancy groups in August and I expect to see those small ice bodies closer to leaving Yosemite entirely glacier-less.

Luckily, because we are causing the current rapid changes in climate, we should have some influence over it. Let's work to reduce our mistake and bring back snowy winters.

Saturday, February 17, 2018

Winter Bypass

We really have skipped past winter here again. Aside from last winter, this has been a season much like those winters of 2011-2016: mild and dry. There's still time for some catch-up precipitation, but it's extremely unlikely to make up for the absence of storms so far. I was up at 7500' along the shoulder of Half Dome with BK the other day. We explored an abandoned trail and stopped by G. Anderson's spring and cabin site; there was barely any snow to speak of.

Above Rancheria Flat (El Portal), numerous flowers are blooming: poppies, red maids, Erodium, woodland star, Nemophila, popcorn flower, fiddlenecks, blue dicks, Stellaria, dead nettle, birds-eye gilia, etc. Some buckeyes are still tight buds, while others are dazzling green with 10cm leaves out. Elderberries are also leafing out. Redbud still seem a ways off.

The Merced River is running below average. It's displaying the diurnal cycle of snowmelt, draining the water that's supposed to flow off in April/May. The aridity of the season means a poor showing for the Horsetail Fall 'firefall' phenomenon but crowds are coming nonetheless; viral imagery from other years seems to matter more than natural reality on the ground. NPS and YC have arranged an impressive structure for managing access to the main viewing areas. Without more than a wet streak at Horsetail, at least the system gets a dry run. (Yes, intentional.)

Summer stars are rising before dawn now: Scorpio and the Triangle. The Falcon Heavy orbital burn was visible for a few minutes over Yosemite last week, an unexpected celestial apparition.

Wednesday, January 31, 2018

Candy Weather Again

Warm, dry conditions continue in a very poor winter for the Sierra. We've had a few storms and there is some snow (mostly above 7000'), but we seem to be having a weak winter like those of 2011-2015. Things could still change, but this feels too similar to those seasons of poor skiing, thin waterfalls and early fires. The Merced is running just a bit above average volume, but this is runoff that shouldn't be happening until April. Candy weather: it's nice in the moment, but you know it's not good for anyone in the long term.

Fiddleneck, chickweed and blue dick are blooming in the lower Merced Canyon now. I always look for the first fiddlenecks on the grassy bank outside my Yosemite Conservancy office in El Portal; the first optimist opened 16 January. Waterfall buttercups are profuse in their favored locations (first flowers noted 31 December near Ned's Gulch).

I walked up the remnants of the 1856 Coulterville Free Trail the other day. This climbs steeply to the north and west from below Pohono Bridge up the canyon wall toward Tamarack Flat, intersecting with the Old Big Oak Flat Road somewhere west of the road's Cascade Creek crossing. The road was put through to the Valley floor in 1874, so the trail was used by stock and foot traffic for less than 20 years. Like most of the early routes built by Euro-Americans, it was developed not by the government but by entrepreneurs hoping to make a buck from tolls. In places the trail is still clearly built and obvious, in places it's been entirely absorbed back into the landscape since it was replaced by the stage road when Grant (who later visited Yosemite) was president 144 years ago. This photo shows rockwork along Fireplace Creek.

One special traveler who arrived via the Coulterville Free Trail and got his first view of Yosemite Valley was John Muir in 1868. It's interesting to imagine Muir and his traveling companion Joseph Chilwell finishing their walk from San Francisco Bay by leaving the snows of Crane Flat, descending this steep toll path, and seeing the cliffs and Bridalveil Fall. Muir was a nobody when he showed up in Yosemite; he was 30 years old, a transient laborer, who passed through the Valley and Mariposa Grove then went to find work in the ranch country of the lowest Sierra foothills to the west of us. The Valley and the Grove were well-known tourist attractions and had already become protected reserves four years before Muir came to California. More than a year after coming over the Coulterville Trail he came back into the high country above Yosemite Valley tending a herd of sheep and then found blue collar work in the Valley for two years. After that point he was mostly a resident of the East Bay, building a career that included plenty of return visits to Yosemite Valley and the higher terrain to the east. The rest is history. You never know which poor immigrant will go on to change our world so much for the better.

Monday, December 18, 2017

Solstish

Apologies for my long absence; it was a busy summer in Yosemite, and I've been enjoying the recovery. My schedule slows down as the park's does.

Yosemite is truly uncrowded now; I've been hiking where I see no one all day. I went up to Little Yosemite Valley for the night last week, and saw 4 people on the way; in the summertime it'd be 400 people. The campground there was calm and quiet with most nighttime noise coming from a spotted owl and the brightest fires were from Geminid meteors overhead. Half Dome leans completely away from the sun before 5pm and its cold shoulders cool off quickly then. I went up to George Anderson's spring and cabin but no one was there, either.

The Merced has dropped to below average, for just the second short stretch in a year. Yosemite Falls and the others are light but not anemic. There's very little snow at any elevation.

Yesterday was our annual Christmas Bird Count wherein several dozen amateur naturalists spend the day afield accounting for all avians. All-star Michael Ross added the first-ever Say's Phoebes to the count. Thomas Say went to boarding school with John Kirk Townsend (of Townsend's Warbler, for example). Townsend did some of his western natural history work in the company of Thomas Nuttall (of Nuttall's Woodpecker). Nuttall never got to the Sierra but he came to coastal California in 1835 where he bumped into one of his former Harvard students, Richard Henry Dana, Jr. (that's right, "Two Years Before the Mast"). On his second trip to California, Dana made it up to Yosemite and spent time with Galen Clark. Clark, of course, is buried in the Valley's cemetery, the residents of which Michael and I think of as some of the people from our village. Even after all these years we are 4 degrees of separation from the fellow for whom the phoebe is named.

Winter solstice is at hand, when the darkest days will start to stretch and lighten a bit. Here's hoping the Sierra gets Nevada and all of us range in the light soon.

Thursday, June 29, 2017

A solstice to remember

Our remarkable year continues to surprise with storms into June. The Merced River has hovered near flood level for several weeks, running 3-5 times usual volume. Only now is it showing a typical seasonal decline, more than a month later than 'normal.' Low elevation tributaries are already drying or dried, but the main stem still runs strongly.

The lower canyon shows an interesting color reversal of early spring's redbuds underlain by white Nemophila or Claytonia, whereas now it's the white of buckeye overlying the purple of Clarkia.

Steve's newest Yosemite Nature Notes video has been released; you can learn something about Yosemite's grizzly bears here. How would your Yosemite visit be different with grizzlies around? Here's a brief travel item on Yosemite in the Huffington Post. Both of these media items have something in common with this blog...

Tioga Pass opens to cars today, but don't expect any services in Tuolumne to open soon. Likewise, hiking will be quite challenging for a while because of lingering snow and high runoff. (Do not take chances with stream crossings!) This IS an exceptional year and we won't see the high country we've become used to.

Monday, April 3, 2017

Post-winter Recovery

Springtime is making its way uphill in the Sierra with redbud peaking in El Portal now while unfathomable snow persists above 7000 feet. It can hardly be said enough: WHAT a winter we've had here! Storms were repeated with good frequency and lots of Pacific moisture, leaving us with a tremendous snowpack. The snowline was a bit higher than historical averages; not much accumulated in Yosemite Valley (though we had lots of rain runoff), but higher elevations have had fantastical quantities. The central Sierra has 175% of usual water content in the current snowpack. Picture the meadows and forests in the May Lake area buried by 6-7 feet of water (not 6' of snow, but 6' of standing water) - that's the nature of how much mature, dense snow is covering the tens of thousands of acres of Yosemite's upper elevations.

<-Bridalveil in flood.

Storm damage has been considerable in/near the park, with Hwy. 41 having been closed for a month by a washout, and crews working hard to repair slope movement on the Big Oak Flat Road below Crane Flat in hopes of getting it re-opened before Memorial Day. Trails at and above the Yosemite Valley level have a lot of downed trees; trail crew sawyers will be very busy for much of the summer to get those cleared. When you visit the Valley, check out the fragments of bark-less logs below Bridalveil or Yosemite Falls from trees that were uprooted and thrown over the falls this winter. Since December there's been a huge deposit of frazil (wist) ice below Yosemite Falls, and we're now in the month when one is most likely to be able to observe wist ice flowing.

The excitement isn't over. Because of the closure of the Big Oak Flat Road, Hwy. 140 has been handling much more traffic. This past Saturday, visitors were waiting over 2 hours in a 3.5 mile-long line of 800+ cars just to get through the stoplight at the Ferguson rockslide detour west of the park. (Easily avoided by coming in before 9am on weekends.) Because of the road construction in the Valley, the main parking at Yosemite Village will be closed for the next two months, and detours are confusing to both new and veteran visitors. It's going to be a very nice improvement once it's completed, but parking and navigating can be challenges on spring weekends now. Half Dome Village and the new lot by Camp Four are best bets. The road crew is already working to clear Glacier Point Road.

But, wait, there's more. The Merced is running almost 4x average flow today. All that snow in the high country seems likely to bring us some degree of 'high water incident' between now and mid-June (sure to cover some Valley trails at least), depending on how the warming progresses. Yosemite explorers should expect a delayed start to summer, with Tioga Road opening late, trails covered by snow and fallen trees, and creeks difficult to cross.

Saturday, January 28, 2017

Ice, Ice, Maybe

There's an exceptional accumulation of waterfall slurry ice below Yosemite Falls right now, and the whole amphitheater is closed for safety reasons. The stream of 'frazil' flow meanders dynamically and it'd be possible for someone to get into real trouble with this unstable landscape. We know it's not really 'frazil ice' because this slurry is formed of frozen waterfall mist/droplets, but it's remarkable, whatever we call it.
There's frazil deposition in Royal Arch Creek and Steve B. says there's frazil in Bridalveil and Ribbon Creeks.

There's also a very healthy snowpack at higher elevations, well above average in depth and water content. The Valley has lots of water from recent storms; there's almost a foot of snow on the ground but running water in Sentinel, Eagle, Royal Arch, Ribbon and other creeks. This wet winter bodes well for summertime waterfalls, some groundwater recharge, and perhaps a more normally-timed start to the fire season. We'll have to wait a few months to fully assess the end of the drought.

Meanwhile at lower elevations flowers are blooming in the Merced River canyon: fiddleneck, baby blue eyes, and a galaxy of waterfall buttercups can be found.