Finding a parking spot for our Ford F-350 pickup, the 22-feet-long and six-wheeled towing unit of The Goddard, is sometimes a challenge. We usually just park on the outskirts of businesses’ parking lots because, unless the parking spots are oversized, we sometimes take up more than one space. When visiting Yellowstone National Park in September, we realized that we needed to get early starts in order to find spaces in the park’s parking lots: we arrived after Labor Day and park rangers assured us that visitation had noticeably dropped, but parking spaces were still at a premium beginning in the late morning hours, So it was when we visited Norris Geyser Basin, located in Yellowstone’s northwest quadrant: we arrived at about 8:30 AM on September 12 and happily found a parking space. It was already getting pretty chilly in mid-September: high temperatures in the basin that week were in the mid-60s Fahrenheit (about 18 degrees Celsius) and pre-dawn low temperatures were in the low to mid-30s Fahrenheit (about 0 degrees Celsius).
Those cold air temperatures combined with the hot steam rising from abundant geothermal features to create an otherworldly effect; it was extremely foggy, which made it difficult to discern any of the geysers, hot springs, and other features. The day soon warmed up, however, and the features revealed themselves. There are two different loop walks around Norris Geyser Basin: the longer and more forested Back Basin, which we visited later the same day (see that posting for an explanation of the different types of hydrothermal features, which I won’t repeat here), and Porcelain Basin. Here’s a look at some of what we saw in Porcelain Basin, once the air cleared a bit.
Those are some impressively large logs. This is the north-facing side of the Norris Geyser Basin Museum, designed by architect Herbert Maier (1893-1969) and built between 1929 and 1930. The museum, at 7,560 feet (2,304 meters) in elevation, was our first stop at Norris while we waited for the fog to dissipate. Maier also designed three other buildings in Yellowstone National Park: still-standing museums at Madison and Fishing Bridge, and the Old Faithful Museum of Geothermal Activity. Together, the four structures, built in an architectural style known as “National Park Service Rustic” that attempted to connect manmade buildings with the natural environments in which they were constructed, interpreted the geologic features on the Grand Loop road. Unfortunately, the museum at Old Faithful was demolished in 1971 to accommodate a new visitor center; that structure was itself demolished to make way for the current visitor center that opened in 2010. Maier also designed still-standing buildings in Yosemite National Park in California and Grand Canyon National Park in Arizona, as well as a number of structures in state parks in Texas.This picture, I think, really captures the extraordinary beauty and kaleidoscopic color of Yellowstone National Park. (Not really: it captures the foggy conditions at Porcelain Basin for the first hour or so after our arrival.) This hillside is venting sulfuric acid, gas, and steam, and the colder temperatures on the morning of our visit made the venting look quite pronounced. Norris Geyser Basin is the hottest area in Yellowstone National Park, in which one only needs to dig four miles downward to find magma – rock that’s so hot that it has become liquified (one wouldn’t necessarily want to do that, though). The average surface temperature in the basin is 280.4 degrees F (138 degrees C), and a probe sent 1,086 feet (331 meters) under the ground’s surface registered a temperature of 464 degrees F (240 degrees C). A vent from which gases and steam escape is called a fumarole (from the French fumerolle, which is a domed vented structure built over a stove to allow steam and smoke to escape); a fumarole that vents sulfuric gases (like these in the photo) is called a solfatara, while a fumarole that vents carbon dioxide gases is called a mofetta. A muffuletta is a delicious Italian sandwich popularized in New Orleans, but that’s not important right now.These pools, collectively called Porcelain Springs, give their name to the basin. They’re supposedly very pretty when the sun is shining on them, but I guess we’ll never find out for sure. The white mineral surrounding the bodies of water is called siliceous sinter, also known as geyserite. The silica is brought to the ground surface by the hot water in the pools, and accumulates very slowly – about an inch per century. Relatively new sinter is white; as it ages it turns to a darker gray color. The hydrothermal features in the greater Norris Basin, including both Back Bay and Porcelain basins, contain the highest level of silica in Yellowstone National Park – it’s what contributes the white milkiness (some might say porcelain-like) attribute to these bodies of water. Other minerals, like iron, arsenic, and sulfur, are all abundant as well. The latter contributes a distinct aroma to walks around these basins.This photo, too, is indicative of what we saw while waiting for the fog to go away. As you can see, Porcelain Basin is not a terribly inviting place if the sun isn’t shining. These trees, interestingly, found the conditions in the soil conducive to germinate, grow, and mature into tall pines; the soil conditions later changed because of geothermal activity in Porcelain Basin and made the ground inhospitable to many lifeforms. Most of Norris Geyser Basin is walkable only on boardwalks like this one: the ground is too fragile (and, remember, it’s nearly 300 degrees) for visitors to walk on directly.I took this photo from about the same position as the previous one (the boardwalk is just to the right side of the image), but looking slightly to the left and about half an hour later. You can see the sun was starting to emerge but steam is still rising from Nuphar Lake, which is itself not a geothermally heated body of water – it’s just plain old steam evaporating as the air temperature rises. Nuphar Lake (nuphar is a genus of flowering aquatic plants) has an interesting recent story, however. In 2021 and 2022, the lake’s water level rose by several feet (about one meter). Apparently, a geothermal feature near the lake began sending silica-laden water into the lake rather than into Porcelain Basin, which turned the lake’s water cloudy-white. The water level rose so dramatically that Nuphar Lake threatened to overflow its banks and into Porcelain Basin (which would have been pretty bad, because there are a lot of really pretty features there). By the end of the summer of 2024, though, the water level receded to its previous level and the color of the water returned to its normal clear green. Geologists found that an earthquake that occurred in April 2024 near the lake created a 10-foot-wide (about 3 meters) crater and caused water to stop flowing from the hydrothermal features. The dead trees in the previous photo, and those in the foreground of this photo, were killed by the silica-rich hydrothermal water that had been flowing into Nuphar Lake. That’s one big takeaway from our visit to Yellowstone National Park: nothing’s ever the same, and you can’t count on anything being there on a subsequent visit.Well, well, well … look what decided to finally show up: the sun. This is the same Porcelain Springs body of water that’s in the upper-left corner of the image three photos up. A sunny day does make all the difference – they are very pretty after all. Like porcelain, almost.The steam in Porcelain Basin, made more prominent because of the morning’s cold temperatures, was finally starting to dissipate so that we could see what else the basin had to offer. The sun was already pretty high up in the sky by that point, but it made for an interesting look. No retinas were damaged in the taking of this photo; the steam was a lot denser than it looks in the image.This is Hurricane Vent, which once was a fumarole but has increased in size to include more water action as well as a small waterfall on its side. It was pretty noisy, and interesting to watch.I took this photo just a few steps down the boardwalk from Hurricane Vent. This is looking to the southwest and at Ledge Geyser, which, while it rarely actually erupts, was certainly impressively active and loudly spouting steam from several of its vents during our time in Porcelain Basin. When Ledge does erupt, the geyser sends water more than 80 feet (24 meters) into the air. The Norris Geyser Basin Museum is on the other side of Ledge Geyser and up a hillside in this photo.Here we’re looking northeast from the Porcelain Basin boardwalk and at Constant Geyser. When it erupts, Constant’s spouts of water can reach 20-30 feet (6-9 m) into the air, but last only about 10 seconds. The geyser can go 20 minutes or several hours between eruptions.A few steps down the boardwalk, Whirligig Geyser (on the right) has eruptions that can be heard throughout Porcelain Basin. That green-hued stream on the left is the East Fork of Tantalus Creek.Here’s a closer look at the East Fork of Tantalus Creek. In Greek mythology, Tantalus was one of the (many, many, many) sons of Zeus who, for whichever transgression(s) you might choose to believe, was sentenced to stand in a pool of water under a fruit tree. The fruit was forever just outside his grasp, and, when he bent to get a drink, the water below him always receded. Anyhow, the beautiful green color of this creek comes from the thermophiles, or heat-loving microorganisms, that live in the water, in particular Cyanidioschyzon (I did not, despite how much I would have liked to, make that word up). It’s a genus of algae that thrives in water that’s 100-126 degrees F (38-52 degrees C). The steam from Whirligig Geyser is obscuring them in this photo, but there’s also a population of red-colored thermophiles that is thriving in hotter waters (122-160 degrees F, 50-60 degrees C) closer to Whirligig’s opening. The red coloration comes from the iron oxide that is in the geyser’s outflow. You’ll recall from high-school biology and chemistry classes that the pH scale is used to measure the concentration of hydrogen ions in a chemical. The scale goes from 1 (most acidic) to 14 (most alkaline), with 7 in the middle at neutral. Some of the water features in Norris Geyser Basin have a pH value below 2; they’re nearly as acidic as vinegar. It takes a tough little organism to live in that hot, acidic environment.This body of water, situated near the end of the Porcelain Basin loop, is Crackling Lake, named for the popping sounds made by geysers seen on its shoreline on the left.Here’s a last look at Ledge Geyser. This photo was taken from the other side of the plume of steam from where I took the previous photo of Ledge (note the other folks on the boardwalk looking at Constant, Whirligig, and other geysers to the left-center of the photo). Even though it never erupted, Ledge Geyser was a most impressive hydrothermal feature that made it hard to forget that molten rock was just four miles below our feet.
After a brief respite in the parking lot (and our prime parking spot) for lunch, Nancy and I enjoyed the features of Back Basin. We saw a lot of hydrothermal features that day – fortunately the fog over Porcelain Basin lifted about an hour after our arrival so that we could see them – and my guess is that the next time we visit, we’ll see a difference in a national park in which nothing is ever truly the same.
Works Consulted
Lynne, Bridget Y. “The Geothermal Guide to Yellowstone National Park.” 2017.
National Park Service. “Norris Geyser Basin Trail Guide.” March 2024.
National Park Service interpretive signage at Norris Geyser Basin Museum and at features throughout Porcelain Basin.
Wikipedia, accessed October 2025. If you use Wikipedia, please support it.
Norris Geyser Basin, located in the northwest quadrant of Yellowstone National Park, is one of the most active hydrothermal regions in the park and contains rare types of geysers within a geologically active earthquake area. The basin is located near the intersection of three major ground faults, helping to create the conditions for Norris’s significant geothermal activity. It’s outside the huge Yellowstone Caldera, the basin that remains after a titanic volcanic eruption 631,000 years ago, but within another 2.1-million-year-old caldera.
Nancy and I spent nearly all of Friday, Sept. 12, 2025, at Norris Geyser Basin. Named after Philetus W. Norris, the second superintendent of Yellowstone National Park, the geyser basin has two decidedly different trails: a short 3/4-mile (1.2 km) loop through the Porcelain Basin, and a longer 1.5-mile (2.4 km) loop with stops at geothermal features in the Back Basin. Both geyser basins are at an elevation of about 7,600 feet (2,316 m). Both trails involve the use of many boardwalks to keep visitors from walking too close to the heated features, and the ground is very thin in many spots and bad things would happen if someone broke through (and bad things do happen when someone decides to ignore the rules). I’ll write a posting detailing the Porcelain Basin later; for now, here are some of the sights to see and smell at Norris’s Back Basin, which includes the world’s tallest active geyser.
Before we get started though, let’s review hydrothermal features. Yellowstone National Park’s hydrothermal features are created by magma, which is partially molten rock, remarkably close to the park’s surface. Water, either from snowmelt or rain, percolates downward through faults and fractures in the earth’s surface and then, after making contact with the hot rock formation, rises back toward the surface and collects in open channels that serve as the hydrothermal features’ water supplies.
Geysers, perhaps the most familiar type of hydrothermal feature, form if the channel has a constriction of some type that pressurizes the water. Temperatures in the superheated and pressurized water below the constriction create steadily amounts of steam, which is eventually pushed through the constriction and an instantaneous drop in water pressure below the steam creates an eruption. These events can be fairly predictable, as in the case of Yellowstone’s Old Faithful, or irregular, with intervals between eruptions lasting unpredictable numbers of days, weeks, or even longer.
If a channel doesn’t have a pressurizing constriction, a hot spring is formed as superheated water comes to the earth’s surface, cools somewhat, and is replaced by hotter water beneath it.
The hottest hydrothermal features in Yellowstone National Park, fumaroles, are steam vents in which channel systems have little access to water, and whatever does reach the surface is immediately converted to steam with a temperature greater than that of water’s boiling point (212 degrees F, or 100 degrees C, at sea level).
Finally, mudpots are created when rock around a hydrothermal feature is converted, by acid, into clay. When it mixes with water, the clay forms mud of different colors and viscosities. Gases in the feature bubble up through the mud to make interesting sights, sounds, and smells.
All hydrothermal features are susceptible to changing environmental conditions. If access to water is changed, or the fissures around a feature are altered because of seismic activity, the feature’s activity could change dramatically or even cease altogether. Many geysers, for instance, that were active in years past are now quiet.
The first stop on the Back Basin Loop is this very pretty 27-foot-deep pool, Emerald Spring. The color of a particular hot spring can help determine what minerals that spring contains. Water in a relatively mineral-free clear blue spring, for instance, absorbs all of the colors of sunlight except for blue. Emerald Spring contains significant deposits of the mineral sulfur, the yellow color of which combines with the reflected blue sunlight to create this beautiful shade of green. The temperature of the water in this spring is close to the boiling point, ensuring that only the most heat-tolerant microorganisms, or thermophiles, can survive in this environment. There’s plenty of sulfur in this spring, which is used by some thermophiles as a source of energy. The byproducts from the sulfur’s usage in turn are used by other thermophiles, resulting in a kind of recycling process that creates something like thermophile interdependence.Next up is the world’s tallest active hydrothermal feature, Steamboat Geyser. Although there was a lot of steam evident, Steamboat Geyser on the day of our visit was relatively quiet with just a few intermittent spurts of water measuring a few feet high. When it goes, though, Steamboat really goes: it is capable of shooting steam and water up to 300 feet (91 m) into the air. That’s the distance of a football field. Prior to 1904, Steamboat was not the tallest geyser in the world. That honor belonged to a geothermal feature in New Zealand, Waimangu Geyser, which shot water a mind-blowing 1,600 feet (488 m) into the air. A landslide changed the water table around Waimangu, however, and it hasn’t erupted since.
Here’s the thing about Steamboat that’s really wacky: its eruptions are extraordinarily erratic. In the nearly 30 years between 1990 and 2017, Steamboat erupted 12 times (including one interval between eruptions that lasted almost 9 years). Between March 15, 2018, and May 7, 2023, a little over five years, the geyser erupted 165 times. We visited in mid-September 2025, and Steamboat’s last major eruption had occurred on April 14 – five months earlier. Before then, it erupted on Feb. 2, 2025, a little over two months earlier. In all of 2024, Steamboat erupted six times. Nature is chaotic sometimes, and it’s beautiful. Note the huge desolated treeless area in the photo above. The geyser’s eruptions, helped by prevailing southerly winds, caused that destruction.
Cistern Spring is located downhill from Steamboat Geyser – I didn’t measure the elevation change, but it’s at least 50 feet lower, and the boardwalk trail has a couple of switchbacks. However, Cistern Spring is connected underground to Steamboat because it empties completely whenever the larger geyser erupts. The brown, green, and orange colors in Cistern Spring are created by different species of thermophiles. The dead trees around the spring were killed by the silica in Cistern Spring’s water: conditions around the spring were once healthy enough for the trees to germinate, grow, and mature, but then the conditions changed. We saw that a lot all over Yellowstone National Park: big areas of trees that had been killed by changing hydrothermal features.This feature has one of the best names in the Back Basin. It’s Black PitSpring, and it started off about half a century ago as a group of steam vents. Water now continuously bubbles with very small eruptions at its surface.Here’s a closeup, using a telephoto lens, of the little eruptions from Black Pit Spring. It’s a pretty mesmerizing hydrothermal feature, with a great variety of colors (not so much black, though).This is Echinus (pr. e-KI-nus) Geyser, perhaps my favorite feature in the basin. It is named for its mineral deposits, which apparently look the spins of sea urchins (neither Nancy nor I are overly familiar with echinoderms like sea urchins, but we didn’t see anything that resembled sea urchin spines). The red color is due to high concentrations of iron oxide (rust) in the feature. Echinus’s eruptions, which can reach 60 feet in the air, are unpredictable and are now months and even years apart. From 1878 to 1948, the geyser rarely erupted but then moved to periods of relative high activity alternating with dormancy. Prior to 1998, it was on an eruption schedule of about every half-hour to 90 minutes. The scientists believe that something happened underground in 1998 to affect the geyser’s water source. For now, it’s a fairly large and very pretty pool of water (see the guy emerging from the trees on the boardwalk just right of center for scale).This photo was taken on the other side of the geyser from where the previous photo was taken, i.e. just to the right of the guy on the boardwalk in the photo above. Echinus Geyser is a beautifully complex hydrothermal feature, even if we can’t make out the sea-urchin-ish spines.Here’s one of the reasons why Echinus Geyser appeals to me so much: these are terrace formations on the geyser’s southwest side where water leaves the geyser. I took this photo at about the same spot as the photo above, but used my telephoto lens again. These terrace mats are formed by unthinkably large numbers of a microorganism called Archaea (pr. aar-KEE-ah), which is a an immense domain of life that precedes kingdoms (you remember, from high-school biology, the memory aid “Kings Play Chess On Fine Green Sand,” or Kingdom, Phylum, Class, Order, Family, Genus, Species; domain is a step above kingdom). Water coming from the geyser is 176.5 degrees F (80.3 degrees C), and has a pH of 3.3 to 3.6 – it’s nearly as acidic as vinegar. At this point in the terracing, the temperature drops to between 140 and 160 degrees F (60 to 71 degrees C). Archaea absolutely love this hot and acidic water, and survive on the energy produced by iron oxidizing in the geyser’s water then bind together to build these ridges, pools, and ripples. Archaea are very common in nature: different types are found everywhere on the planet, including other features in Yellowstone National Park, and your gut, mouth, and skin are covered in them right now (not the same ones in this picture; remember that Archaea covers a lot of different species, let alone all of the other Kings Playing Chess). It’s extremely likely that when the scientists do find irrefutable evidence of extraterrestrial life, it will be in the form of Archaea or something close to it. This is a view a little further down the boardwalk from Echinus Geyser. That small river of water is flowing northwesterly from the geyser – it’s a pretty desolate landscape in the river bottom, but remember that the river has a pH nearly equal to that of vinegar. Notice also the steam rising from the ground where the river meets the trees in upper left; as the scientists say, this is a geothermally active area, and that is evidence of yet another geothermal feature.This is Porkchop Geyser, so named because of its shape when viewed from above and which only intermittently erupted until 1985 when it started spouting on a continuous basis. Those eruptions wasn’t enough to keep the geyser’s constriction from building up tremendous pressure and four years later, on Sept. 5, 1989, this feature exploded with a violence sufficient to throw large rocks more than 200 feet (61m). Fortunately, the tourists present for this surprise event weren’t injured. Porkchop’s vent hole at times has been the diameter of a garden hose; after the explosion, it’s about 7 feet in diameter. After that event, Porkchop became a gently bubbling hot spring with only occasional – and unpredictable – geyser eruptions.Even if it didn’t erupt while we were there, Veteran Geyser was a lot of fun to listen to. The area in shadow in the lower right corner of the picture is a vent through which Veteran exhaled with what sounded like someone in severe respiratory distress. A couple with whom I’d briefly spoken at Steamboat was here admiring Veteran as well, and, realizing that we were nearing the end of the Back Basin loop, the woman asked what our favorite hydrothermal feature was. I quickly answered with Echinus Geyser, and asked what her favorite was. She said it was Black Pit Spring, but mostly because of the name. I couldn’t disagree with her. In a basin filled with features named Green Dragon Spring, Puff ‘n Stuff Geyser, and Black Hermit Caldron, Black Pit Spring does still manage to stand out.At the time when Yellowstone’s visitors toured via stagecoaches, Minute Geyser erupted every 60 seconds to heights of 40 to 50 feet (12-15 meters). Inexplicably, many of those tourists tossed rocks into one of the geyser’s vents and eventually plugged it. While it continuously spouts water about 3 feet (0.9 meter) now, it’s unknown whether the feature will ever fully erupt again. Signs warning tourists to not throw rocks, coins, or other objects into park’s hydrothermal features were all over Yellowstone. I just can’t wrap my head around why someone would want to do that in the first place.The Back Basin loop trail ends with a short hike up a hillside, resulting in this magnificent view of Norris’s other geyser area, the Porcelain Basin. I’ve got pictures of the features within Porcelain Basin as well, and will post those in the near future.
There are about 25 named features within Back Basin, so this was a look at less than half of what’s there. Walking around any of Yellowstone National Park’s hydrothermal areas gets you really close to all kinds of aspects of our natural world, and it’s easy to think that it’s always looked the way it appears today. But conditions underground, like earthquakes, heat changes, mineral buildup, and more, ensure that these features are anything but timeless: a geyser can become a hot spring (and vice versa), for instance, because of subtle and usually unseen geologic changes.
It was a fun day at Norris’s Back Basin, and one that Nancy and I will appreciate for a long time – especially because the next time we go, it may be significantly different.
Works Consulted
Lynne, Bridget Y. “The Geothermal Guide to Yellowstone National Park.” 2017.
National Park Service. “Norris Geyser Basin Trail Guide.” March 2024.
National Park Service interpretive signage at features throughout Back Basin.
Wikipedia, articles on Archaea, Echinus Geyser, and Steamboat Geyser. Accessed September 2025. If you use Wikipedia, please support it.
Tales of The Goddard 