Biblical Plague or Culinary Opportunity? A day in the California Prairie Lands

We journeyed out to the California prairie lands again today. We've now paid a visit in the fall, the early spring, and now the late spring, as summer starts to take hold in the Sierra Nevada foothills. Our destination was a small stockpond in the hills south of Knight's Ferry on the Stanislaus River. The local bedrock is composed of vertical exposures of metamorphic slate and greenstone with a covering of andesite lahar (volcanic mudflow) deposits called the Mehrten Formation.

We had one of the best rainfall seasons in many years, with around 115-120% normal rainfall, and an unusually cool April and May. When we were here in early April, the ground was muddy, and the grass was green. There were quite a few birds, but when we got there this evening, it was a great deal busier, even though the grass is brown. Part of the busy-ness involved things being splattered on the windshield and being crunched under the tires. There was a regular plague of grasshoppers, thousands upon thousands of them everywhere. Apparently the conditions were ripe for a population explosion.

I've heard of some serious problems with grasshoppers in the midwest this year, with aerial spraying of pesticides and the like, but I don't think it was going on here. There was a much more normal way of dealing with the overpopulation of the pest: birds were munching away! I'm not entirely sure why the birds were all lined up, but there was a small drainage next to the road, and I suspect the grasshoppers were more abundant on the particular stretch of road.

It's kind of creepy to get out and walk among the insect plague, as hundreds jumped away in all directions. I leaned down to take a shot of a bee in one of the few flowers, and I honestly did not notice the grasshopper looming over the flower. In fact, if you look carefully, you may notice that at least four grasshoppers were stripping away the leaves and flowers.

Still, it was peaceful in the twilight, and the songs of hundreds of satiated birds and bullfrogs was a pleasant musical accompaniment to the dying sunlight.

UPDATE: I suspect we saw an 'irruption' of devastating grasshoppers. Apparently they have caused some real problems in the past, especially in the late 1950's.

El Capitan is Gone! Where in the World is Carmen Sandiego?*

Whatever will we do?? What is Yosemite without El Capitan? Is it worth visiting? Well, as I've said before TURN AROUND! There are so many treasures in the valley, and today's feature is no exception. Almost everyone stops near El Capitan Meadow to look for climbers on El Capitan, and as I watch the crowds with their binoculars, few of them are ever looking at the valley wall to the south. Where else in the world would cliffs like these not be a national landmark all on their own? Welcome to Poosenachucka, which means the Large Acorn Cache (most people these days call them the Cathedral Rocks and the Cathedral Spires)!

The cliffs at Cathedral Rocks are only 500 feet shorter than the 3,000 foot precipice of El Capitan on the north side of the valley. Both are composed of the relatively unjointed and therefore highly resistant El Capitan granite. The largest glaciers that moved through Yosemite Valley around one million years ago (the Sherwin stage) scoured out deep basins approaching 2,000 feet deep in the upper valley, but the ice river was constricted at the "gateway" between El Capitan and Cathedral Rocks, and the sediments below the valley floor there are only 300 feet thick.

The glaciers of the younger Tahoe and Tioga stages only reached the base of the two cliffs, and had nothing to do with the sculpting of the high cliffs. A series of terminal and recessional moraines are found on the valley floor beneath the steep walls of granite.

Of course, it's hard to ignore El Capitan when you stand beneath it! Once again, a series of pictures provide a sense of scale of these immense cliffs. The picture above is a view of the entire cliff from near El Capitan Meadow. Zooming on the vertical cliffs near the summit, one can see a diagonal crack casting a shadow. Can you see a dot to the left of the crack?

Zooming in again, we see a pair of climbers working their way up the cliff. The climb is usually a 2-3 day expedition. When we left the valley in the late evening last week, we stopped at El Capitan Meadow to look at the stars. To our surprise, five or six of the "stars" were actually the flashlights of climbers on the cliff settling in for the night.

*For the uninitiated, Carmen Sandiego was a popular computer franchise that involved the theft of unusual objects like the Eiffel Tower.

Omigosh, They Sold Yosemite Falls to Retire the National Debt! Whatever Will We Do??

I think they're gonna use it in a new amusement park!I'M KIDDING! I just wanted you to think about something. Yosemite Falls is just spectacular this time of year, but would you visit Yosemite Valley if you didn't get to see it? Is there another reason to visit the valley, waterfall-wise? I got to see two nice candidates during the high runoff last week. It is true that both of these falls dry up relatively quickly in the late spring or early summer, but when they flow, they are world-class. I saw the first of these from a new spot last week...somehow, I've never stopped at Bridalveil Meadow before (in 80 trips!!). Viewed from the southwest edge of the meadow, Ribbon Fall leaps off the cliff and falls for 1,612 feet, making it the highest single drop of any waterfall in the valley (Yosemite Falls drops 2,425 feet, but does so in three parts, the tallest being 1,430 feet). Combined with the west face of El Capitan, it makes for a memorable view.

Here is a closer view from Bridalveil Meadow. The entire fall can be seen from the large pullout at Bridalveil Falls view. You just have to turn around and look away from Bridalveil Fall, and many people seem to miss it.

Another fall that reaches for majesty in the spring runoff is Sentinel Falls, which drops 1,920 feet in five steps, the largest of which is 500 or so feet. It is accompanied by the incredible Sentinel Rock, to the left in the picture below, one of the other "not always noticed" rocks in Yosemite. I call it that because to see it, you have to turn and look away from Yosemite Falls, if you can. It's behind you!

If you ever have a chance to see Yosemite in the spring, go for it! If not, enjoy the pictures, it's the reason I put them up (and I would like to see some more spring pictures from the places I can't get to, too).

5.7-5.9 Aftershock in Southern California

Big aftershock to the El Mayor - Cucapah Earthquake, just over the border in California, at 5.7 or 5.9 (awaiting confirmation from the USGS). It has been followed by more than a dozen aftershocks of magnitude 3.0 or higher. I would imagine it has been felt widely in southern California.

This is a good reminder to be prepared for the larger quakes to come. The San Andreas system has a great deal of accumulated stress that has to be relieved pretty soon.

Update: 5.7, after review by seismologists

High Water in Yosemite III

We continue our journey through Yosemite Valley during the peak runoff last week (part I here, and part II here), when the Merced River exceeded 7,000 cubic feet per second, and reached flood stage. Numerous meadows and trails were underwater, and it was a wonderful thing to see! Above is the view from in front of the chapel at Old Yosemite Village. The slope on the right is the lower part of the Three Brothers, with the Cathedral Rocks in the distance.

And above we have a flooded portion of the meadow at the base of El Capitan. Once again, we are looking at the incredible Cathedral Rocks with the Cathedral Spires on the left.

The gaging station that measures the discharge of the Merced River is just upstream of Pohono Bridge. The problem with bridges is that we tend to put them at the narrow parts of river channels. When the floods come, the bridges can cause a bottleneck effect, having all kinds of implications upstream and downstream. Some of the bridges have been redesigned in recent years to allow the river to flow in a more natural pattern and to stabilize bank erosion.

As noted in the previous posts, floods are not a particular problem for the natural ecosystems of the valley. The ecosystem developed under a seasonal pattern of flooding and drought. The floods can be a minor inconvenience to hikers on the valley floor, as in the picture above where the riverside trail is flooded.

Trees that grow too close to the river will have their roots inundated. If the flood lasts for any period of time, the trees will suffocate and die. Usually the high water backs off within a few days. Today, a week after my trip, the river is flowing at 3,160 cubic feet per second, half of what it was a week ago, but still about 50% above normal for the middle of June.

Update: Martha at Martha's Musings was in Yosemite at the same time. See some nice pictures here.

A Few Snapshots for a Sunday: High Water in Yosemite II

I talked in yesterday's post about the familiar places in Yosemite, places like Yosemite Falls. There is a reason they are famous, and seemingly the focus of almost every tourist picture: they are truly spectacular, especially at times like last week when the runoff is at a peak. I have hundreds of pictures of Yosemite Falls, and as of Tuesday, I have two dozen more!

The Merced River was at flood stage, running at almost 7,000 cubic feet per second, and a number of meadows were filled with overflow from the river. You can see how the walkway is flooded in the picture above. Floods like this are not at all a bad thing, at least not from a natural point of view (displaced tourists may disagree). The flooding brings in new sediment, and floods out tree roots, preventing young saplings from encroaching on the meadows.

Yosemite Falls is unique in the way that it plunges over a vertical cliff, dropping 1,430 feet in an unbroken fall. The water collects into a series of rarely seen cascades for 700 feet before finally tumbling over 320-foot Lower Yosemite Fall for a total drop of 2,425 feet. By various measures, the fall is the highest in North America, and somewhere between the 5th to the 20th highest in the world (Angel Fall in Venezuela in the highest in the world at 3,458 feet).

I was always intrigued by the cleft to the left of the falls. It looks like a river channel, but carries no water to speak of, even during high runoff periods. The trail to the top of the waterfall employs the break in the cliff to reach the valley rim. I thought about it, but never had the insight I needed to complete the story. N. King Huber filled in the story in his wonderful book, published posthumously, Geological Ramblings in Yosemite. I've told the story in a previous post, but in a nutshell, the river used to follow the left channel until it was diverted by a glacial moraine during one of the last ice ages, causing it to spill over the cliff instead.

And what a plunge it makes! I've spent many happy hours of contemplation, just watching a single pulse of water break over the cliff, and follow just that pulse for the quarter mile drop.

From the valley floor, the water seems to spring from the cliff without an obvious source, but a look at the falls from Glacier Point on the south rim of the valley shows that there is clearly a drainage area above. The road to Tuolumne Meadows traverses the headwaters of Yosemite Creek, and there is a small campground on the creek several miles upstream from the falls.

Yosemite Falls is a familiar sight, but it never once has looked the same to me. Every visit has been different, and last week it was spectacular!

BP and BS...Stuff from All Over

The Washington Post gets it right...gas is very...expensive (via Twitter at @clasticdetritus). There is a lot of blood mixed in with the oil we consume. The apology needs to come from us.

A bit of anger from Rant Hour...How good are Tony Hayward's predictions and proclamations? Remember Bagdad Bob ("the Saddam spokesman who coalition forces would never take the capital even as American tanks were visible a few thousand yards from where BB stood")?

A 1962 ad for Humble Oil from Al's Journal, via Huffington Post. Humble Oil became Exxon in the 1970's. Big Oil definitely isn't humble any more...

From Mike Mitchell, via Huffington Post

And, BP continues to block media access to the devastated beaches with the help of the local and federal government...

Gasoline and petroleum are not our only energy related problems...those gas-saving lithium ion batteries in hybrid car also have a problem with resource availability. Lithium has to be mined too.