Wednesday, August 25, 2010 : Yellowstone National Park


We are going to spend the whole day in Yellowstone National Park. What we will see really makes our time more than worthwhile !


Yellowstone is 3/4 the size of Connecticut. That means that, in a whole day, we will see most of it, but certainly not everything. Here, too, we had to make choices.


This park is located on the Rocky Mountains range. All day long, we will be going up and down, between about 6,200 and 8,800 ft. The Continental Divide, the line that separates waters flowing into the Atlantic from those flowing into the Pacific, crosses the southwest part of the park. About 80% of the park area is on the Atlantic side.


But the reason why Yellowstone is famous is, by and large, its intense volcanic activity, which, nowadays, is mostly represented by the numerous geysers, fumaroles, thermal springs and other incarnations of an extreme diversity. A giant caldeira, left over by the last major eruption 640,000 years ago, occupies more than 1/3 of the park. Considering its size, I would not want to be there when the next eruption happens. From what it seems, half the world's geysers are in Yellowstone, the other half being shared between Iceland and a few other places.


Geysers are essentially grouped in basins. There are about 10 major basins, we will see most of them.

Yellowstone National Park, Monument Geyser Basin

First stop, Monument Geyser Basin


Our first stop is at Monument Geyser Basin. Do no get misunderstood, most geysers are actually small. Among the 2,000-plus geysers in Yellowstone, only a handful, such as Old Faithful or the Giant really move moutains of water.


Notice the footbridge in the background. Those footbridges are present in most of the geyser basins in Yellowstone. They have been appropriately placed to give access to the most interesting sites, and at the same time avoid burning or drowning hazards. In Yellowstone, in all volcanic activity basins, the ground is very hot and very acid. Useless to say, it is absolutely prohibited to wander away from the footbridges.


Yellowstone National Park, Norris Geyser Basin

Norris Geyser Basin


We proceed on the loop road that crosses most of the park, on which most interesting sites are located.


Our second stop is at Norris Geyser Basin, a larger basin that requires a longer walk. Leaving from the parking lot, the trail goes down to a footbridge, from which we can see a dozen of geysers.


Yellowstone National Park, Norris Geyser Basin

Steamboat Geyser


This one, the Steamboat Geyser, is very appropriately named. It whistles and exhales a thick smoke, like a steamboat. The grey traces, on the right, are what remains of the mineral deposits left by the geyser, once the steam has condensed into water.


Yellowstone National Park, Norris Geyser Basin

Norris Geyser Basin

The nice rusty color of mineral sediments at the bottom of this geyser has a bacterial origin. Acids emitted by the geysers are fixated by waterborne bacteria. How a living organism can survive in such a hostile environment, with  a pH commonly around 1 (the pH of pure water is about 7 !) remains one of the major mysteries of species adaptation. Everywhere in Yellowstone, we will see more of those brightly colored formations, each time bacteria fixated in a particularly acid environment.

Of course, do not try and dip your feet in the basins !


Yellowstone National Park, Pearl Geyser

Pearl Geyser


Still in Norris is the Pearl Geyser, a nice reference to the the shape and iridescent reflections of water drops emitted by the pressurized gases flowing from the bottom of the basin.


Yellowstone National Park, Norris Geyser Basin

Norris Geyser Basin


Back at the visitor center, after walking the trek around the basin, we take this nice panoramic picture. From here, we can see pretty well the relevance of the wooden footbridges. Without them, there would be absolutely no way to get close to the geysers.


We also see that the acidity of the ground formally prevents any vegetation from growing. This bareness is not the consequence of some ancient eruption. On such an acid ground, simply nothing can grow.


Yellowstone National Park, Roaring Mountain

Roaring Mountain


Later on, we stop at Roaring Mountain. Nowadays, the moutain does not really roar, it more or less whistles, a bit like a pressure cooker, and for about the same reasons, pressurized vapor escaping thru various cracks in the rock.


Yellowstone National Park, Lower Terraces

Lower Terraces


We then cross the Golden Gate, which has nothing to do with San Francisco's. This one is a very narrow pass between two mountains that the road crosses on a kind of bridge hooked to the side of the mountain. It's quite spectacular !


We later stop at the Upper and Lower Terraces, above Mammoth Hot Springs. These terraces are the upper part of the "falls", which are not actually falls. They are rather bacterial and mineral accumulations, that ended up giving these multi-colored terraces where water escapes after having leaked thru various cracks in the volcanic rock.


Yellowstone National Park, Mammoth Hot Springs

Mammoth Hot Springs


The volcanic water flowing from the terraces gave the Mammoth Hot Springs, this huge pile of various calcareous minerals, mostly travertine, basically sodium carbonate. It's hard to imagine that the tiny water creeks from the Terraces have fixated so much mineral, but, at the pace of two tons a day for a few tens of millennia, the result is here.


Yellowstone National Park, the Petrified Tree

The Petrified Tree, 50 million years old


This petrified tree is a witness of a bygone era, the Eocene, when Yellowstone was much warmer and more humid than nowadays. This tree is biologically identical to the  California sequoias. During an eruption, it was instantly petrified by volcanic ash, without having the time to burn. This is what allows us to see it today like it was during the Tertiary era.


As a sidenote, once again, the picture is absolutely unmodified. The sky really had that beautiful deep blue color.


Yellowstone National Park, Yellowstone River

Yellowstone River


Yellowstone is not only about volcanic activity. It is also the Yellowstone River, a Missouri tributary that basically splits the park in two, south to north, by a canyon of varying depth. We are here at the lowest part of the canyon, almost at the north of the park.


Last but not least, Yellowstone is about this yellowish limestone that you can see on the right of the canyon, hence its name of "yellow stone".


Yellowstone National Park, Tower Fall

Tower Fall


Between the lake, that we will see later, and the north end of the park, Yellowstone River loses about 2,000 ft of elevation in 25 miles. Useless to say, its course is broken by several falls. This one is Tower Fall, the last major fall inside the park.


Yellowstone National Park, Lower Fall

Lower Fall


We have now reached Canyon Village, roughly the geographic center of the park. The place is accurately named, it dominates the most spectacular part of Yellowstone Canyon, and gives access to the Upper and Lower falls. Paths allow people to get quite close to both falls, and get sprayed in the process. There is also a spectacular point of view, Lookout Point, where we took this picture of the Lower Fall.


Yellowstone National Park, Yellowstone River rapids

Just above the Upper Fall, the stream is already strong


A bit further, this view of the river just above the Upper Fall really shows the intensity of the stream. No way to ride a kayak here !


Yellowstone National Park, bison

Yellowstone and its bison


Between Canyon Village and the lake, we cross a large plateau where hundreds of bison live. The animals, hunted in all the Western plains except at Yellowstone, a national park since 1872, took shelter here to escape mass slaughters. With food and water in abundance, they proliferated, while at the same time they were dying off everywhere else. Today, the bison is a protected species, but it has not always been the case. Just ask Buffalo Bill !


Yellowstone National Park, the Mud Volcano

The Mud Volcano


We make another stop at a small geyser basin where we take a few pictures, including this one, showing a small pond where a few gas bubbles percolate. Of course, it is another volcanic activity. In Yellowstone, Mother Nature has been very generous in her diversity.


Yellowstone National Park, Yellowstone Lake

Yellowstone Lake


At the end of the afternoon, we drive along Yellowstone Lake. After the tumult of the falls and the shrill whistling of geysers, we hugely enjoy the quietness of this landscape. It is restful for both eye and ear. Well, next time, we'll rent a boat !


Yellowstone National Park, Old Faithful at sunset

Sunset behind Old Faithful


As the sun sets behind the mountain, we are at Old Faithful. We are not willing to wait for the next eruption of the most famous geyser in the park, and probably in the world. We will come back tomorrow.

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