Wednesday, February 3, 2016

You CAN See Half Dome from the Central Valley. But You Have to be in the Right Spot

A field in the Central Valley!
Living in California's Great Valley has moments. Some good, some bad. It's really flat, and that isn't of much interest to a geologist (except the drilling kind). But on some days, when the storms have blown through, and the wind has pushed all of the smog and dust to other places, the valley is beautiful. The best days are when the snow-covered Sierra Nevada are visible in the east.
Some intense contrast brings out the mountains in the distance. This is about how Half Dome appears to the naked eye
I live directly west of Yosemite Valley, and the question has come up now and then whether Half Dome, the iconic rock of Yosemite, is visible from the valley floor. Half Dome rises 4,000 feet above Yosemite Valley, dominating the local view. But it is surprising to some to find that it is surrounded by peaks of equal or greater elevation, and as such, it is not easy to see from the floor of the Great Valley. But it is possible, if you are in the right spot...and have binoculars or a camera with a good zoom lens.
We start zooming in...the snow covered dome of Half Dome is dead center.
That spot is a narrow corridor that runs southwest from Denair through Turlock to Patterson. It's in this location because Yosemite Valley is angled in a southwest direction, providing a gun-sight towards the Central Valley. There are a handful of other spots, but this is the easiest to find. I was out at the junction of Keyes and Hickman Roads this afternoon, and although it was hazy, I was able to pick out the dome from the surrounding peaks. To see it in these photos took a lot of contrast and manipulation (but not of the Photoshop kind!)
Half Dome at 120x zoom. Note the mountains behind Half Dome.
The issue arose today because of the absolutely glorious day we had yesterday. A sharp-eyed employee at StanEmergency in downtown Modesto took a photograph of the gorgeous skyline, and in the center of the photograph was a prominent peak that looked a heck of a lot like Half Dome. He or she posted the photo on Facebook (here), and it quickly garnered more than a thousand likes, 800 shares, and more than a hundred comments. I had to do a double take, because that peak was unusual looking. Very Half-Dome-like, so to speak.
Credit: https://www.facebook.com/StanEmergency/
I was a little surprised, because I knew the peaks behind Half Dome are much higher, and that Half Dome shouldn't be so prominent from this angle. I had managed to get a shot of the same peak from my neck of the woods in Waterford the same day. I hit the maps, and asked for suggestions from Geotripper readers in my last post (this one). I got a good tip from twoeightnine, who suggested it might be Mount Clark, which would be almost exactly behind Half Dome from the perspective of Modesto.(UPDATE: Almost immediately after I posted this, another commentator, Lucas Wilkinson, posted this from CalTopo that shows that the peak in question is Volunteer Peak, not Clark. I was looking in the wrong direction!)

Mount Clark is 11,522 feet (3,512 meters), almost 3,000 feet higher than Half Dome, and it has a steep northern flank that could easily mistaken for the shape of Yosemite's iconic rock (EDIT: Unfortunately I don't have any closeups of Volunteer Peak!).
Photographer: Greg Cope (Prints for sale here)
Visitors who get out of Yosemite Valley and travel to Glacier Point are treated to spectacular view of the peak. It is a spectacular mountain, a marvelous example of a glacially carved horn, surrounded by glacial cirques, the bowl shaped valleys where glaciers originated (EDIT: If only I'd been right! But Clark is a pretty mountain).
It's really something that so many people took an interest in their geologic surroundings. And it was so nice to have such a dramatically clear day. We could use more of them. And thanks to StanEmergency for posting a great picture and mystery project!

Tuesday, February 2, 2016

Time for the Topographer's Challenge! What Peak is this in Yosemite National Park?

Actually, I want your help here. I don't know the peak with the vertical flank on the right side of the picture above. I took this shot yesterday from near the intersection of Wellsford and Milnes Roads between Modesto and Waterford. I was looking east or just north of east when I got the shot.

The thing is this. There's an intense discussion on a facebook post (see it here), with some strong opinions that it is Half Dome. I don't think it is, because I've photographed Half Dome from the valley on a number of occasions (here, here and here), and it just doesn't have this kind of topographic prominence from the peaks that surround it. I also can't related to the peaks that should be around it, like Clouds Rest, and Sentinel Dome.

But I'm left with this. If it isn't Half Dome, what peak is it? I think it's north of Yosemite Valley, and I think that the white peak on the far left of the first picture above is Mt. Conness. Could it be Mt. Hoffman? Anyway, your expert guidance and half-formed opinions are equally welcome!

Monday, February 1, 2016

Green and White in California...There's a drought here? Why yes...yes there is

What a sight for sore (and dry) eyes. Deep emerald fields of growing grass, and snow-capped peaks in the distance. Tropical palm trees. Spring? Hardly. It's the first of February in California, a place mired in the depths of the worst drought in perhaps a thousand years. Somehow, the picture doesn't fit with the reality, but it unfortunately does.

I was headed home this afternoon and the passing storm had cleared the air in our valley, exposing the Sierra Nevada near Yosemite National Park in all its glory. I believe we are looking at Mt. Hoffman on the right and Mt. Conness on the left (I am open to other opinions, maybe Matterhorn Peak on the left?). I was looking east from the latitude of Milnes Road east of Modesto. Lots of snow up high, growing fields below, and puddles and mud everywhere.
What do you think? Conness or Matterhorn?
It's certainly not the lack of rainfall. I've been following precipitation in my small town of Waterford in California's Great Valley since 1991, and we've had three great months in a row, 2.82 inches in November, 2.6 inches in December, and 5.3 inches in January (5th wettest January in 25 years, and compared to 0.0 inches last year). We have reached 11.10 inches for the water year, the wettest in all but three of the last 25 years by the first of February (only the El Nino years of 2005 and 1998, and 1995 exceeded this amount). If not a single drop were to fall the rest of the year, this would still be wetter than seven of the past 25 years. But more rain is likely, as El Nino remains a powerful influence in California storms, and there are three more months left in the rainy season.
The snowpack reports are the best in years, ranging from 107% to 120% in the Sierra Nevada and Cascades. Last year? We ended up with a snowpack that was less than 10% of normal.


So how can the drought maps be practically unchanged from several months ago? All of the state remains in drier than normal, and 40% of the state remains in "exceptional" drought. How can this be? It's because we fell so far behind. If the breadwinner in a household loses his or her income, the family will live off of savings for a while, and as unemployment drags on, the family starts using the credit cards. They get into a deep financial hole. When money starts to come in again, basic needs are once again met, but it takes a long time to build up the savings and pay off the credit cards. That's where we are in California right now. Water is returning, but the reservoirs are exceedingly low, and even worse, groundwater has been overdrafted like never before.
A family has one out, a do-over of sorts. Bankruptcy. They could start over with a cleared financial slate. But when it comes to water and California, we don't have that option. We have what we have, and it's going to take a lot more water from the skies to get us back to "normal", if such a climate condition exists anymore.

California Department of Water Resources: http://cdec.water.ca.gov/cdecapp/snowapp/sweq.action

U.S. Drought Monitor:  http://droughtmonitor.unl.edu/Home.aspx

Thursday, January 28, 2016

Dreams of Summer: Going Underground on New Mexico's Continental Divide


When one thinks of the Continental Divide, one might imagine high peaks of the Rocky Mountains, piercing the sky with glacially carved ridges. It's not always quite that way. As we made our way last summer across the flat plateau lands east of Petrified Forest National Park, we passed the Zuni Pueblo, and reached a forest of Ponderosa pines.
The flat highway crossed a barely perceptible rise, and we almost missed a sign that said we were crossing the Continental Divide. Somehow, we had driven to an elevation of more than 8,000 feet and barely noticed. We crossed the divide and entered El Malpais National Monument.
It was late in the day and we were on a tight schedule, so we didn't have time to explore this strange and wonderful landscape as much as we might have wished, but we couldn't pass up the chance to go underground for a while.
El Malpais (Spanish: "Bad Lands") lies at the edge of the Colorado Plateau where it drops off into the Rio Grande Rift. The rift valley a vast fault trough where the continent started to split apart starting 30 million years ago. Rifting is never a gentle process, and the tearing of the crust allows magmas to form and erupt. Most of El Malpais National Monument is a geologically recent series of basalt flows, the youngest ranging in age from 2,500 to 17,600 years ago.
Basaltic lavas are more fluid than silica-rich lavas like andesite or rhyolite. They can flow for miles before cooling, but the flow is aided by the formation of a crust on the surface. The crust acts as insulation, keeping the lava hot and fluid. At times, especially near the end of the eruption sequence, the lava drains from under the crust, leaving behind a system of linear caves called lava tubes. That's what we were visiting that evening. There are undoubtedly many lava tubes in the park, but four are specifically open for exploration.

Junction Cave is several hundred feet long and is easily accessed at the end of a short trail off the main highway. If you intend to visit, be sure to get a free permit from the visitor center. The cave is bat habitat, and the park is extremely worried (with good reason) that the white-nose fungus might attack the bats. The fungus has decimated bat populations back east, and has been moving west over the last few years.

Lava tubes are not "decorated" in the manner of limestone caverns, as solution (the origin of stalactites and the like) is not a prominent process in the volcanic rocks. On the other hand, there are occasionally flow structures and drip structures ("lavacicles") that can be seen. Some of the caves may even preserve ice masses long after winter has ended (there is a commercial ice cave at the park boundary).

New Mexico is famous for caves, Carlsbad Caverns being one of the premier caves of the world. But in some little forgotten corners there are interesting caves of a completely different kind.

Tuesday, January 26, 2016

Late to the Party, but here's the 7.1 Magnitude Alaska Earthquake as Recorded from Central California


An earthquake, large by California standards, but almost moderate by Alaska standards, hit on Sunday, January 24 southwest of Anchorage. It measured 7.1 on the magnitude scale (moment magnitude). The quake was on a strike-slip fault (lateral motion), and was thankfully relatively deep (128 km/80 miles). Deep is good because the waves had to travel 80 miles just to get to the surface; it's like being 80 miles away from the epicenter of a shallow quake. Because of this, the damage was minor.

Our recording device is a simple classroom demonstration seismometer, but it has proven capable of catching a good record of large distant quakes, and smaller local ones. It's available for less than $1,000 at science supply outlets like Wards Science.

Monday, January 25, 2016

A Modesto Junior College Field Studies Opportunity: Geology and Archaeology of the Hawaiian Islands, June 1-13, 2016



This might be of interest only to my Modesto area readers, but anyone who is interested in learning about the natural and human history of the Hawaiian Islands may want to investigate this field studies opportunity June 1-13, 2016.

Imagine yourself on a journey exploring volcanoes, coral reefs, deep mysterious canyons rivaling the Grand Canyon, tropical rainforests, tropical deserts, ancient foot trails and petroglyphs while learning geology and archaeology in one of the finest outdoor laboratories on the planet! The Hawaiian Islands are scientific and cultural treasure! Our MJC summer field studies course  will be a multidisciplinary study of the Hawaiian Islands, with nine days on the Big Island, and four days on Kaua'i. This will be a dyad class, Geology 190 and Anthropology 190. Cost for lodging, transportation and inter-island flight will be $2,200 (students will need to meet us in Hawaii, and arrange their own food). An informational meeting will be held Thursday, January 28 (5:30 PM in Science Community Center Room 326). We welcome the participation of interested students, community members, and staff members at MJC.
Contact me (hayesg "at" yosemite.edu) for more information. There is a course web page at http://hayesg.faculty.mjc.edu/Hawaii_2016.html, and a facebook group page at https://www.facebook.com/groups/452708258272005/. If you can't make it to the information meeting in person, please contact us; we'd be glad to have you join on this great expedition!

Wednesday, January 20, 2016

The Rains Come and the Snow Falls: Normal in California Doesn't Feel Normal

Normal just doesn't feel normal.

In 2014, researchers were declaring the California drought the worst in 1,000 years. And then we had a year, 2015, that was in many ways much worse. We actually had near normal rainfall on the valley floor that year, but it was so warm that the snowpack ended up at 10% of normal, a value never recorded previously. It has been a horrific time. Not only are the reservoirs low and agricultural fields dying away, groundwater has been overdrafted at catastrophic rates, and the worst wildfires in living memory have destroyed vast swaths of forests in the Sierra Nevada and Southern California.
Dry Creek, January 20, 2016
It's not going to get all that much better. Climate models are suggesting that megadroughts, lasting decades, will be the norm starting in about 30-40 years. So this year has been one of hope, in California anyway. El Nino, the climate phenomena that causes all kinds of chaos across the world, tends to bring lots of rain to California (it also unfortunately brings drought elsewhere).

The storms so far have actually not been directly related to El Nino. They have been cold arctic storms that have been dropping prodigious amounts of snow in the Sierra Nevada. For the first time in five years, the snowfall has been above normal. Not far above normal, around 110-115%, but it feels unprecedented after such a long period of paltry precipitation.

The climate of the floor of the Great Valley is semi-arid to desert. The winter rains don't contribute much to the agricultural yields, but wet years are important, as they allow for some recharge of the groundwater. It's never been enough, so our groundwater "savings account" is always shrinking overall.

So I've been watching the precipitation pretty carefully of late. Well, actually I've been tracking rainfall amounts in my backyard rain gauge since 1991, and this year has been interesting. At 2.82 inches, the November rain was the second highest I've recorded. December didn't set records, but 2.60 inches fell that month. But once January arrived, the spigots opened up, and we've four good storms already, dropping 4.21 inches. We've already reached 10.01 inches for the year, where 12 inches is average for an entire season.
Dry Creek on January 7, 2016
Two weeks ago, I noted that Dry Creek, a minor tributary to the Tuolumne River, was "flooding". The earlier storms had only been percolating into the dry soils upstream, but the first heavy storm in January ran off, producing a flow in excess of 1,000 cubic feet per second. We got two more inches of rain in the last three days, and Dry Creek was flowing at nearly 3,000 cubic feet per second this morning. It was a delightful sight.
Dry Creek in March 2011, at more than 3,000 cfs
The future is hard to predict. Last year, we had a wet autumn, but there wasn't a single drop of rain in January, and what little snow had fallen quickly melted away. According to the climate models, the El Nino storms will be starting to affect California in a matter of weeks, bring intense warm storms, primarily to Central or Southern California. There can be no doubt that we need to fill our depleted reservoirs, if for no other reason than to stop depending on groundwater during the irrigation season.
Merced National Wildlife Refuge, January 2014
But I also worry about the health of our regional wild habitats. The wildlife refuges of the Great Valley are critical roosting places for millions of migratory birds, and they tend to be at the low end of priority for water allocations. The rivers that I love, the Merced, the Tuolumne, and the Stanislaus, have been running low and warm, killing tremendous numbers of native fish, and allowing the spread of invasive Water Hyacinth. We've taken over 95% of the natural habitats of our valley, and have a responsibility for taking care of what little remains.

It's been normal, but it doesn't feel normal.