Our Incredible ‘Yellowstone’ Holiday: Part III – The Yellowstone Caldera and Geysers of the Old Faithful Basin

A Journey of Education in Volcanic Eruptions

Upper Geyser Basin, Yellowstone National Park

Sunset at the Upper Geyser Basin, Yellowstone National Park. Photo: Nurin Merchant. Copyright.

Previous parts:

Our Incredible ‘Yellowstone’ Holiday: Part II – Wild Life Safari at Grand Teton National Park
Our Incredible ‘Yellowstone’ Holiday – Part I: Salt Lake City

On Wednesday, July 20th, after completing the wildlife and scenic safari at the Grand Teton National Park, we continued with our drive that would now take us to our ultimate destination – the Yellowstone National Park. We reached the South entrance via the John D. Rockefeller Memorial Highway, stopping along the way at various tip-over look-out points to see the Lewis Canyon and its swift flowing river.  The South Side completes the 8 loop of Yellowstone National Park, and is home to one of the earth’s richest geyser basins, with the iconic and world-famous Old Faithful Geyser giving it the added exposure and publicity which it deserves. This basin area is known as the Upper Geyser Basin (or the Old Faithful Basin).

The iconic Old Faithful Inn at the Upper Geyser Basin in Yellowstone National Park is a National Historic Landmark The Inn was built of local logs and stone in the early 1900s, adjacent to its namesake geyser. The Inn offers excellent accomodation, lounges, restaurants and a gift shop. Nearby is the Old Faithful Lodge which also offers great views of the Old Faithful geyser. Photo: Nurin Merchant. Copyright.

We reached the Upper Geyser Basin around 5-6 pm and had three good hours to go before dusk. Should we therefore cover the basin or wait until the following day after seeing the Lower and Midway Geyser Basins, since they were all on the lower half of the loop (see map below)? When we parked the car near the Old Faithful Lodge – the Old Faithful Inn is next to it – I was short of energy and not quite prepared to tackle the recommended 2.4 mile trail trip that would take us to the “must see” Morning Glory Pool and back. Teenagers are great motivators. Nurin, perhaps from the treadmill run at Teton Village, was vibrant and energetic and was prepared to take the lead. By finishing the Old Faithful Basin, we would have more time for other things to do in the Park, she suggested. Why waste the three hours before sunset? I felt rejuvenated. We took an excellent trail map from one of the wooden boxes for 50 cents (optional) and off we ventured for the geysers. We suggest you get a trail map that are located in small wooden boxes at the start of each trail – and please pay the 50 cents as it helps support the Park – and keep the map for future reference or, alternatively, return it to one of the boxes.

Yellowstone National Park – Igniting Imagination

Giant Geyser, Old Faithful Basin, Yellowstone National Park

Giant Geyser, temperature 202.7°F, became dormant in 1955, and has slowly become active since and erratic. During 2007 it erupted more than 50 times; during 2009, only once. Its spectacular eruptions last about an hour and can reach 250 feet (76 metres). Photo: Nurin Merchant. Copyright.

Yellowstone, as a whole, possesses close to 60 percent of the world’s geysers. It gives one lessons in chemistry, biology and geology among other subjects. It highlights issues related to the environment and makes one wonder why people sometimes do silly things. Yellowstone is spectacular.

Heart Spring received its name because of the heart-like shape of the crater. It is 8×13 feet and has a depth of 16 feet. Heart Spring has had temperature fluctuations from 150-202°F. This wide range of temperature has allowed microbial growth to form varicolored patterns. This spring is typical of many of Yellowstone’s thermal springs. Nearly 10,000 thermal features exist in Yellowstone and many are alkaline hot springs similar to Heart Spring in size and appearance. One feature which distinguishes each is the bright, colorful cyanobacteria and algae which grow along the edge of run-off channels. Each spring has its unique pattern. Photo: Nurin Merchant. Copyright.

The geysers are one of the features that makes this Park truly unique and why I brought my daughter here. Moreover, besides geysers, the Park has spectacular scenery, wildlife, rivers, falls and its most popular attraction, the Grand Canyon of Yellowstone. It embodies the features of all the other National Parks in North America and virtually everything is present here. That’s what makes it so fascinating.

Grotto Geyser has always had an interconnecting relationship with the Spa and Rocket geysers. The temperature of the geyser is 201 °F, and it erupts at an interval of 1 hour to 2 days. Duration varies (3 hours for short mode and 9-13 hours for long modes). It reaches a height 20-30 feet. The eruptions consist of a series of powerful splashes, steam and the discharge of nearly 150 gallons per minute. Deep gurgling and splashing sounds are constantly emitted from the vent. It is an unusual shaped formation nearly 8 feet high. Photo: Malik Merchant. Copyright.

The Yellowstone Caldera and the Hydrothermal (Water + Heat) Features Today

The Yellowstone Crater – or Caldera – the rims of which Nurin and I drove over – was formed about 640,000 years ago – yesterday in geological time. A large magma chamber (molten rock) formed within the earth and over time the heat from this magma not only melted the lower layer’s of the earth’s crust but pushed it upward with tremendous pressure, stretching and thinning it.

A pictorial explanation of Yellowstone’s hydro-thermal features at a board walk. Photo: Malik Merchant.

The pressure intensified so much that the chamber exploded with a terrific force, spewing volcanic ash thousands of miles away. As all this material emptied out of the chamber, the crust that rested on top of it collapsed creating a volcanic crater – 40 by 30 miles across. Scientists call this crater a caldera. No recent eruption compares the magnitude of that Yellowstone force: it was 7500 times bigger than the Mount St. Helens’ eruption of 1980, and 200 times bigger than the Krakatoa eruption which eliminated 66% of the 12 square mile uninhabited East Indian island.

Grand Geyeser eruption time notice placed at the site by the Park’s wardens. Photo: Malik Merchant. Copyright

Even today, the Yellowstone National Park is in movement all the time! There is continuous volcanic activity and we are reminded of Yellowstone’s powerful past through a wonderful display of geysers, hot springs, mudpots and fumaroles, which have replaced erupting volcanoes and flowing lava.

i. Geysers

Grand Geyser Yellowstone

The power and spectacle of a Grand Geyser eruption inspired the name given by the 1871 Hayden Expedition. It is one of the few major geysers that has not changed considerably since its early discovery. This fountain-type geyser erupts from a shallow basin which slowly fills with water over a 5 hour period. Two adjoining geysers, Turban and Vent, are separated by a thin narrow bridge. Its temperature is 201°F. Photo: Nurin Merchant. Copyright.

Geysers are hot springs with narrow spaces in their plumbing, usually near the surface.

The origin of the word is Icelandic and it means “to gush.” Rain or melting snow percolates through layers of porous rock and the water sinks to a depth of nearly 10,000 feet, almost 2 miles, where it comes in contact with heat from the magma chamber, where the water is super-heated. Its temperature rises to well above the boiling point but it doesn’t boil because of the immense weight pushing down on it from the rock and water above. The highly energized water is less dense than the water sinking around it, and is pushed upward toward the surface through cracks in the rock. As it rises, steam forms. Bubbling upward, steam expands until the bubbles are too large and numerous to pass freely through the constrictions or narrow sections in the plumbing. This creates a traffic jam. At a critical point, the confined bubbles actually lift the water above, causing the geyser to splash or overflow. This decreases pressure on the system, and violent boiling results. Tremendous amounts of steam force out of the vent, and the eruption begins.

Water is expelled faster than it can enter the geyser’s plumbing system and the heat and the pressure gradually decrease. The eruption stops when the water reservoir is exhausted or when the gas bubbles diminish enough to be able to rise without ejecting the water.

Riverside Geyser Yellowstone

Situated on the bank of Firehole River, Riverside Geyser is one of the most predictable geysers in the park. During its 20 minute eruptions, a 75 ft (23m) column of water arches gracefully over the river. Eruptions are about 6 hours apart. The temperature is 201.2°F. Photo: Nurin Merchant. Copyright.

ii. Hot Springs

Hot Springs on the other hand lack the essential constrictions found in geysers. The hot water is unimpeded on its ascent and circulates freely at the surface. Mixing with cooler water from above, the hot spring may boil or gently steam. The hottest springs are usually clear blue in colour. This is because the temperature is too hot for all but the sturdiest of microbes to survive.

iii. Mud Pots

Mud pots are sometimes called Paint Pots because of all the colours they display. They occur when the supply of hot water is limited and hydrogen sulphide gas is present. Some micro-organisms use the hydrogen sulphide for energy and produce sulphuric acid as a by-product. The acid in turn dissolves the rock around it into mud. The result is a gooey mix that burps and bubbles.

iv. Fumarole

The fourth and final type of hydrothermal feature in Yellowstone National Park is a steam vent, technically called a Fumarole. It is the hottest of all the features. In the case of the Fumarole, the water supply is so limited that what little of it there is, boils away before it reaches the surface, converting all water to steam. The hiss or roar that one hears is the sound of steam rushing up through the underground plumbing system. Fumaroles are easier to see in cool weather.

The Upper or the Old Faithful Geyser Basin

Yellowstone has it all, invoking visions of erupting geysers, colourful hot springs, mud pots and hissing fumaroles. The pictures and captions on this page represent the geysers and hot springs at the Old Faithful Geyser Basin. Future segments will cover other unique geysers at the National Park.

Chromatic Pool and the nearby Beauty Pool are related and are among the most colourful pools in the geyser basins. Their colors begin with a deep blue center radiating out to yellow, orange and red. When one pool begins to overflow, the water level in the other drops. This periodic shifting in energy is accompanied by a 10°F change in temperature. In recent years the water temperature has cooled to around 164 to 175 °F (73 to 79 °C) allowing an increase in bacteria and algae growth and a resulting change in color. Photo: Malik Merchant. Copyright.

Of the 10,000 hydro thermal features in the entire Park, the best known is Old Faithful Geyser. It is located just behind the Old Faithful Lodge and the Old Faithful Inn and is central to the Old Faithful Basin. From the Old Faithful geyser there are excellent board walks leading to other nearby geysers in the Basin. The Old Faithful geyser itself erupts approximately every 51 minutes to 120 minutes. Thousands of gallons of steaming water thunder into the sky with each eruption. We had missed an eruption minutes before we arrived at the Basin. Thus it was something we planned to see the next day after completing the Lower and Midway Geyser Basins. The plan was to come and watch the Old Faithful eruption, have lunch at one of Old Faithful’s excellent restaurants and complete the day by visiting the West Thumb Geyser Basin by Yellowstone Lake.

Castle Geyser has a temperature of 200°F and erupts at intervals of 9-11 hours. The duration is around 1 hour, with eruptions reaching a height 60-90 feet. Members of the 1870 Langford-Doane Expedition named this feature for the “resemblance to the ruins of an old castle.” The large sinter cone is nearly 12 feet high with a diameter of 20 feet at the top. Photo: Malik Merchant. Copyright.

During our 2.4 mile trail walk we came across and marvelled at dozens of hydrothermal wonders. Of this remarkable number, only five major geysers are predicted regularly by the naturalist staff. They are Castle, Grand, Daisy, Riverside, and Old Faithful. There are many frequent, smaller geysers to be seen and as well as numerous hot springs. Old Faithful erupts more frequently than any of the other big geysers, although it is not the largest or most regular geyser in the park.

Morning Glory Pool, often referred to as Fading Glory, see next image for why. The temperature of this pool is 171.6°F . It is 23 feet deep, funnel-shaped, and has a dark blue center. The resemblance to the corolla and color of a morning glory is responsible for its name in the early 1880s. It has been a popular thermal feature and a symbol of Yellowstone. Photo: Nurin Merchant. Copyright.

A vantage point 170 ft above Old Faithful provided a spectacular panoramic view of the Basin. Once we reached the Morning Glory Pool at the end of the most popular trail, we made our way back to the Old Faithful Inn. Sadly Morning Glory Pool is now referred to as Fading Glory on the board sign at the pool. Long a favored destination for park visitors, Morning Glory Pool was named in the 1880s for its remarkable likeness to its namesake flower. However, this beautiful pool has fallen victim to vandalism.

A large board explains the state of Morning Glory. Early visitors carelessly removed the delicate scalloped border and dumped debris into the pool. In 1950 the water level was lowered by siphoning which induced the pool to erupt. Socks, bath towels, 76 handkerchiefs, $86.27 in pennies, $8.10 in other coins came up; in all, 112 different objects were removed from Morning Glory. The debris had reduced the flow of water and contributed to the decline in temperature, causing bacteria to grow in the cooler yellow and orange edges of the pool. Photo: Malik Merchant. Copyright

People have thrown literally tons of coins, trash, rocks, and logs into the pool. Much of the debris subsequently became embedded in the sides and vent of the spring, affecting water circulation and accelerating the loss of thermal energy and dropping temperature. Orange and yellow bacteria that formerly coloured only the periphery of the spring now spread toward its center. During our way back we captured some stunning sunset photos.

A dusk view of Castle Geyser as we complete our tour of the Old Faithful Geyser Basin on our first day at Yellowstone National Park. Photo: Nurin Merchant. Copyright.

I had promised a great meal to Nurin at the Inn’s formal restaurant but the seating had closed at 9:30 pm, and we settled at the informal restaurant at the Inn. Nevertheless, the food was great – this was the case at all the restaurants throughout the Park. Good quality and fresh food from pastas to Tacos as well as delicious paninis and sandwiches at reasonable prices. It was almost 10:30 pm by the time we were done, and we had about an hour to drive to West Yellowstone. An orange light appeared quite suddenly on the Camry’s dashboard after a few miles and I ignored it, thankfully. I could not figure this orange light for some reason. Wildlife crossed the road on numerous occasions – mainly coyotes and foxes. The ride felt bumpy, again I blamed this on the surface. After about an hour we exited the Park and soon located our hotel, the Clubhouse Inn and settled down. Nurin, in the meantime, using her Wifi internet access figured out that the Camry’s orange light was from a very low tire pressure.

Our plans to depart the hotel early for the park were jeopardized. When we returned to the car in the morning, we found the front right tire was flat. Am I not glad I ignored the light? Avis were very quick to rectify the inconvenience. The car that we had picked up from Salt Lake City – actually an upgrade – did not meet the standards of upkeep and maintenance that would be expected of a reputable rental car agency. But their computer system had then been down and we took the Camry for lack of availability of other vehicles. Avis arranged for a garage in West Yellowstone to come by and inflate the tire. I drove the car to the agency’s outlet at West Yellowstone airport, anxious about the new car.

The Grizzly and Wolf Discovery Center, West Yellowstone

A grizzly at the Grizzly and Wolf Discovery Center in the town of West Yellowstone. The Center is home for grizzly bears from as far away as Alaska and as close as Yellowstone National Park. Each bear and its story are unique, but they all have something in common; they came to reside here after becoming nuisance bears or orphaned cubs of a nuisance bear. These bears learn to obtain food from people, damage property in search of food or become aggressive toward people and are usually killed. Instead of being destroyed, the eight bears that reside at the GWDC were rescued and are ambassadors for their counterparts in the wild. Photo: Nurin Merchant. Copyright.

Wolves at the Grizzly and Wolf Discovery Centre. The Center is home for 11 wolves that live in three different packs. The wolves were born in captivity and are unable to live in the wild. The wolves eat, play, reinforce their dominance hierarchy and howl right in front of the viewing areas. Many features such as tall grass, logs, trees and a pond with a waterfall give the wolves a very comfortable and natural home. The keepers provide plenty of stimulation by hiding bones or sprinkling spices and other unusual scents. Photo: Nurin Merchant. Copyright.

Nurin, in the meantime, crossed the road from the Clubhouse Inn and  visited the highly educational Grizzly and Wolf Discovery Centre. An almost brand new Ford Fusion awaited me at the Airport. An excellent car, I would say considering my preferences for foreign cars. But anything that is built on a Mazda platform has to have good handling. I collected Nurin around noon and we were on the way, on our second day at Yellowstone, to cover the South Loop of the Park that would also take us to Old Faithful once again and beyond. We had a late start…but then we’d take advantage of the lengthy summer days in the Northern Hemisphere.

Date article posted: Wednesday, August 31, 2011.
Last updated: August 14, 2019.

Copyright: Simerg

Previous Posts:
Our Incredible ‘Yellowstone’ Holiday: Part II – Wild Life Safari at Grand Teton National Park
Our Incredible ‘Yellowstone’ Holiday – Part I: Salt Lake City


Nurin and Malik pictured at the Grand Canyon of Yellowstone. Photo: Simerg. Copyright.

About the authors: Abdulmalik (Malik) Merchant is publisher and editor of this blog. He consults in the Information Technology field as a systems analyst/technical architect in Canada’s capital region, Ottawa.

Nurin, his daughter, completed her high school International Baccalaureate program at the Colonel By Secondary School in Ottawa, and then proceeded to the University of Guelph where she is pursuing an Honours Degree in science with a special focus on Animal Biology.


The article along with the photo captions features material from the following excellent sources:

1. Yellowstone Today, Summer 2011, official newspaper of Yellowstone National Park, National Park Service, US Department of the Interior, free.

2. Yellowstone Explorers Guide by Carl Schreier, Homestead Publishing, Moose Wyoming (1997 edition), $12.95.

3. Yellowstone: The Official Guide to Touring America’s First National Park, published by the Yellowstone Association (Updated edition, 2010), $9.95.

4. Yellowstone Expedition Guide – the Modern Way to Explore America’s Oldest National Park published by Travel Brians, Inc. The book includes a self-guided 14 track CD-ROM that can be played in the car’s stereo system, $39.95.

5. National Geographic Park Profiles – Yellowstone Country, 1997, $19.95.

6. National Geographic – Special Edition Americas National Parks, 2011, $14.95.

7. National Geographic – Greater Yellowstone Region, Geotourism MapGuide, 2009, price unknown, provided free.

8. 99 Things To Do in Yellowstone Country – 2011 Vacation Guide, free.

9. Oh Ranger! Your Complete Guide to the Parks (Yellowstone National Park), published by American Park Network, 2011, free.

10. (Individual) Trail Guides published by the Yellowstone Association, 50 cent donation requested.

11. Grand Teton National Park, National Parks Service, map and pamphlet provided as part of a package when you enter the Park.

12. Geyser Overviews – excellent overviews of all the geysers in the major basins.

13. For official downloadable maps please click, Yellowstone Map and Grand Teton Map.


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