Yellowstone National Park (Part 1: Exploring a Volcano)

I could easily spend an entire month wandering around this massive park, exploring both the wildlife and the fascinating geothermal features that draw life from sitting atop a large super volcano, a massive magma reserve below.  It was vaguely discomforting to know that is what’s behind all of the bubbling, steaming, and spouting water features, but since scientists don’t expect another eruption for the next few thousand years, I walked around feeling like I was getting there just under the wire.


60% of the world’s geysers are located within Yellowstone, which is the largest geyser field on the planet.  Here, there are roughly 500 geysers, and 10,000 hydrothermal features. I’m sharing a virtual tour of several of the regions I visited, with photos and a few videos to give you a sense of what each is like.  Enjoy!

Mud Volcano

The smell, rather than the sight, is the first thing I experienced here.  One of the most acidic features in the entire park, the Sulpher Caldron, is just feet from the main road, and the pungent odor of rotten eggs (caused by hydrogen sulfide gas) permeates the air here.  This part of Yellowstone has the greatest uplift and sinking of the caldera floor, where many faults converge, and earthquakes are common.  There are bubbling pots of muddy water, hillsides strewn with overturned dead trees, and multicolored mats of bacteria.  The walk around the loop trail is .6 mile, and hilly.

I passed the Cooking Hillside, covered by a dense forest until 1978, when a swarm of earthquakes struck the area and ground temperatures soared to 200 degrees Fahrenheit.  The roots of trees cooked in the super heated soil, and they began to topple.  The remnants of the forest are nothing more than dead, bleached and drying tree trunks strewn along the hillside.  1978 doesn’t feel like that long ago, and it was another reminder that Yellowstone is still active.

The trail continues through a series of hydrothermal features, including the Churning Caldron, Black Dragon’s Cauldron and Sour Lake, before heading back down the hill past the Mud Volcano and the eerie Dragon’s Mouth Spring.  The Dragon’s Mouth Spring burst onto the landscape through a crack in the earth in 1948, and the sound of the water bubbling within creates a sort of growling noise before it spews through the opening.

Across the road is for me, the creepiest feature of the entire park; the Sulphur Caldron. The turbulent, churning waters of this caldron have roughly the same level of acidity as battery acid.  As I stood there watching it bubble, it occurred to me that my entire camper would fit in it.


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West Thumb Geyser Basin

This is a caldera within a bigger caldera.  It’s located at the bottom of the Grand Loop (a road that makes a giant figure eight around the park), on the shore of Yellowstone Lake. Hydrothermal features here extend down under the waters of the lake, even into deep water, and I assumed this would mean the lake is warmer, but nope.  Even in summer, the crystal clear water of the lake remains a chilly 45 degrees Fahrenheit.  The exception  is around the underwater vents, where zooplankton thrive.

The trail around the outer loop of this basin is about 1/2 mile, weaving through deep blue springs, mudpots, and down to the lake.  The water in mudpots is highly acidic, dissolving the surrounding rock into clay.  Depending on groundwater and rainfall levels, these can look like either gooey bubbling pots, or solid enough to scoop the clay up for pottery (don’t do this.)


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Lower Geyser Basin (Fountain Paint Pot & Firehole Lake Drive)

This part of the park contains all four types of hydrothermal features: geysers, hot springs, mud pots and fumaroles, although the geysers were the big hit here for me.  This area also contains the only geyser outside of the Old Faithful area with posted eruption forecasts (summer only.)   I walked the Fountain Paint Pot Trail (about 1/2 mile), then went across the road to drive the Firehold Lake Drive (hop out to see the features).

Fountain Paint Pot Trail

This area is on unstable glacial sediments atop solid rock.  In some areas, there is only a thin crust of rock, and the water is acidic enough to burn through boots.  Not to be overly creepy, but dozens of people have died in this area when they left the designated boardwalk (this is illegal for obvious reasons) and hundreds more have been badly scalded.  It’s beautiful, but nature isn’t messing around here, so be sure to pay attention to the signs directing you how to stay safe.

This loop begins and ends with a vista overlooking what appears to be a wasteland.  I got a good look at what are called “Bobby Socks” trees, which are fascinating.  They’re lodgepole pine trees that drowned in the super-heated water, before silica penetrated their base and hardened.  The white silicified portions of the trees give them their names, but to me they have more of a ghost like quality, and they’re beautiful.

My favorite was the Jet Geyser, which I was fortunate enough to see erupt.  The eruptions for Jet reach 20-50 feet and last 25 minutes or more.  It was putting on quite a display when I was there!

Behind Jet is the pool for Morning Geyser, which seldom erupts but when it does, it’s one of the park’s largest geysers, with fountains reaching 8-200 feet.  No such luck while I was visiting, but the view is still quite impressive from that spot.


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Firehole Lake Drive

This is a two mile drive past geysers, hot lakes, hot springs and a hot cascade.  There are parking spots along the way so you can hop out and take a quick peek at the various features.  The Great Fountain Geyser is the main event, with eruptions that average 100 feet, and “superbursts” that can reach 200 feet.  I could just see the end of an eruption from a distance as I drove near, but it takes about 10-14 hours for it to rebuild after that, so I wasn’t waiting around for the next one.  The White Dome Geyser was further down the road, and erupts at intervals anywhere from 30 minutes to 3 hours, so I waited, chatting with a German couple for a bit, hoping to see it go off again.  Luckily, after about 45 minutes we were treated to an eruption.  The large cone has a very narrow vent, so the eruption shot up a good 30 feet (roughly the same height as the cone.)



Midway Geyser Basin (Grand Prismatic)

The Grand Prismatic Spring does not disappoint, and word gets around because this area was overflowing with cars.  I ended up parking on the side of the road and walking about a mile to get there.   Do whatever it takes though, because the color here is fantastic.  As you begin the trail loop by crossing the Firehold River, you’ll see where the Excelsior Geyser faithfully discharges 4,000 gallons of heated water daily over the crater rim, and the area where the water flows into the river is a lively channel filled with brightly colored bacteria.  The geyser itself is both beautiful and intimidating. Photographer Frank J. Haynes managed to capture a photo of it’s last great eruption in 1888, with bursts ranging from 30 to 300 feet high, and there is a display of that impressive shot.  The eruption was so violent that it disturbed the underground system, and eruptions stopped after 1890.  In 1985 however, the geyser came back to life with a series of major eruptions lasting 47 hours.  No one knows when it will erupt next.

The Turquoise Pool and the Opal Pool are next, (following the trail to the right) and in any other place on the planet I would have viewed them as extraordinary, but in the midst of of the colors fantastic, I stopped only briefly before heading on to the main event, the Grand Prismatic Spring.  Here, the boardwalk allows access right up to the edge of Yellowstone’s largest hot spring.  Color, pattern and steamy vapors are all around, along with hundreds of other people who are also trying to take it all in.  I found it to be a bizarre combination of overwhelming natural beauty and careful crowd navigation so that I wouldn’t stumble off the boardwalk.


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Upper Geyser Basin (Old Faithful)

This area is iconic Yellowstone, with it’s famous Old Faithful geyser and the old lodge.  It was fun to walk around, but I was growing weary of crowds and so stayed long enough to see Old Faithful blow, grabbed a bite to eat, and called it a day.  The photos I took weren’t great but here they are:


Fortunately, my youngest offspring is on her own tour of the country this summer, and shared with me this beautiful video she took of Old Faithful erupting at sunset.  Please enjoy this much better representation of a magical spot:


Mammoth Hot Springs

I ended my hydrothermal tour of Yellowstone at Mammoth Hot Springs.  This area is one of the world’s best protected examples of travertine depositing hot springs, which is what forms the terraces.  It’s like a giant colorful sculpture.  You reach the terraces from boardwalks at their base, which are wheelchair accessible. From there, you’ll need to climb to see the upper areas, or there are small upper parking lots (very crowded).  On the boardwalk right at the base, the 37 foot high Liberty Cap formation stands apart and was created by a hot spring that built mineral deposits up over hundreds of years.  The rest of the terraces are in a constant state of change, with new deposits carried to the surface by the water which then trickles down over the changing rock forms.

I decided to simply enjoy the view, and walked around the boardwalks and upper terraces marveling at the shapes and colors.   After an hour or so, I headed down to the visitor’s center where there was a very interesting display on how the National Parks came to be, and the early days of Yellowstone.


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I hope you’ve enjoyed the photos of this beautiful park so far!  My next blog post will also be about Yellowstone, and the wildlife scavenger hunt I took around the park, as well as some lovely landscapes that I found along the way.


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