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.