Midway Geyser Basin and Grand Prismatic Spring: The Largest Hot Spring in USA

The Midway Geyser Basin and Grand Prismatic Spring is one of the most unique and geologically significant areas in Yellowstone National Park. The basin is home to some of the world’s largest hot springs, as well as the world’s tallest active geyser.

Midway Geyser Basin history

The Midway Geyser Basin was formed over thousands of years by the eruption of the Yellowstone Caldera. The caldera is a large, oval-shaped crater that was formed when a massive volcanic eruption occurred.

The eruption ejected so much ash and rock into the atmosphere that it blocked out the sun for several months, causing widespread global cooling.

Yellowstone National Park Grand Prismatic Spring Details
Jason Carter / Sharetheexperience

Since the formation of the caldera, numerous smaller eruptions have occurred within it. This eruption created a large lava flow that can still be seen in the Midway Geyser Basin today.

The hot springs in the Midway Geyser Basin are powered by this ongoing volcanic activity.

Water from rain and melting snow filters down through cracks in the earth’s surface and comes into contact with magma (molten rock) deep below ground.

This heated water then rises back up to the surface, where it forms hot springs, geysers, and other hydrothermal features.

What to see at Midway Geyser Basin?

The Midway Geyser Basin is home to several geothermal features, including geysers, hot springs, and fumaroles.

The most famous feature in the area is the Grand Prismatic Spring, which is the largest hot spring in the United States and third largest in the world.

Other notable geothermal features in the Midway Geyser Basin include Excelsior Geyser Crater (the largest active geyser crater in the world), Opal Pool (a small hot spring), Turquoise Pool (a big hot spring).

Yellowstone National Park Grand Prismatic Spring Map
Yellowstone National Park - Midway Geyser Basin & Grand Prismatic Spring map

Excelsior Geyser

This is the first geyser you come across on your trip to Grand Prismatic Spring as you make your way along the wooden platforms. Excelsior Geyser is one of two large geysers in the Midway Geyser Basin in Yellowstone National Park.

Yellowstone National Park Grand Prismatic Spring Excelsior Geyser
Excelsior Geyser eruption & crater sixthland / Flickr

Although Grand Prismatic Spring is popular today, Excelsior Geyser used to erupt just as well. For a while it was even the largest geyser in the world.

Grand Prismatic Spring

The Grand Prismatic Spring is the largest hot spring in the United States, and is located in Yellowstone National Park.

The spring gets its name from the great amount of heat that causes water to evaporate and form a prism. The spring is about 360 feet across and is surrounded by a boardwalk so that visitors can get a close up view.

Yellowstone National Park Grand Prismatic Spring Close Up
Andrew Parlette
Yellowstone National Park Grand Prismatic Spring Air Look
Eric Henderson

The intense heat of the spring creates an amazing effect on the surrounding area. The water evaporates so quickly that it forms a cloud of steam that can be seen for miles.

The bright colors are created by bacteria that thrive in the hot water. The different colors indicate different temperatures, with the blue being the coolest and the yellow being the hottest.

Why is the Grand Prismatic Spring so colorful?

The spring is formed by heated water from geothermal vents deep below the earth’s surface. The water is heated to over 180 degrees Fahrenheit and is full of minerals and other dissolved solids.

As the water rises to the surface, it cools and the minerals begin to precipitate out, forming the brilliant colors that make the spring so distinctive. The bacteria closest to the center of the spring are red, orange, and yellow due to the extreme heat.

As you move further away from the center, the water temperature decreases and so does the color of the bacteria; green, blue, and purple bacteria are found near the edge of the spring.

If you are interested in how this riot of colors came to be, read The Science Behind Yellowstone’s Rainbow Hot Spring.

What makes the Grand Prismatic Spring so special?

The Grand Prismatic Spring is the largest hot spring in the United States and the third largest in the world.

(The others are The Frying Pan Lake in New Lealand and The Boiling Lake in Dominica) It is located in Yellowstone National Park, Wyoming.

People have been fascinated by hot springs for centuries and this hot spring is no exception. Its brilliant colors and massive size make it a truly unique natural wonder.

How can I get the best view of Grand Prismatic Spring?

There is a wooden platform that goes around the geysers so that you can see them. The best way to see the rainbow colors up close is from the boardwalk that surrounds it.

Using this path, you first cross the Firehole River and then reach the location closest to the geysers. These boardwalks are suitable for wheelchairs or strollers.

Yellowstone National Park Grand Prismatic Spring Overlook
After a short trail to the overlook, you will see this wonderful pool from the viewing platform. Rebecca Latson / Flickr

In addition to the boardwalk, you can see the area from higher up. It’s called the Grand Prismatic Spring Overlook. To get here, walk on the Fairy Falls Trail.

You can also hike down to the overlook on the Fairy Falls Trail. This trail starts at Fairy Falls parking lot and follows the Firehole River for about 0.7 miles before reaching the overlook.

Visiting the Grand Prismatic Spring overlook allows you to take photos of the boiling lake from different angles. You can see a panoramic view of the geyser. It is not a difficult road, it can be walked easily.

When you pass the viewing platform 0.3 miles, turn left and continue 1.30 miles, you will come across a waterfall called Fairy Falls. It is not a great waterfall, but it is preferable if you are looking for an excuse to walk a bit.

Yellowstone National Park Fairy Falls Aerial View
Fairy Falls trail Google Earth

Opal Pool & Turquoise Pool

Opal Pool is the smallest of them all. Due to its small width, it is the pool that gets covered with ice the fastest, especially in winter, and the one that thaws the longest because it does not have enough steam.

Yellowstone National Park Opal Pool
Opal Pool Tashnuva
Yellowstone National Park Turquoise Pool
Turquoise Pool Anak Tok / Flickr

Turquoise Pool, although not as much as the others, is the kind of pool that will amaze people with its color. Like the others, it is important not to get too close to it.

Tips for visiting Midway Geyser Basin

These are among the most dangerous places to visit if you are not careful.

  • While geysers and hot springs are beautiful to look at, they can be deadly if you get too close. The water in geysers and hot springs is incredibly hot. If you fall into one of these water holes, you will almost certainly die.
  • The steam and heat from geysers and hot springs can also be dangerous. It can easily cause serious burns. In addition, the heat from geysers and hot springs can cause dehydration and heat stroke.
  • It is important to be very careful when visiting this place. Make sure you stay on designated trails and boardwalks and never try to touch or swim in the geysers or hot springs.
  • The wildlife around the spring is just as diverse as the colors in the spring itself. Visitors to the area can see elk, bison, deer, pronghorn, and many other animals, so please be respectful and do not approach or disturb them.

By following these simple safety rules, you can enjoy this amazing place without putting yourself in danger.

When to visit the Grand Prismatic Spring?

In cold weather, the hot vapor emitted at low temperatures mixes with the cold air to create dense smoke and fog. Therefore, visiting during the warmer months (from May to September) will allow you to see the colors better.

FAQs about Midway Geyser Basin

How hot is the Grand Prismatic Spring?

The large prismatic spring is one of the hottest springs in Yellowstone National Park. Temperatures range from 63 to 87 degrees Celsius depending on the location.

Can you swim in the Grand Prismatic Spring?

No, you cannot swim there. The water is too hot and the spring is too deep.

Yellowstone National Park Grand Prismatic Spring People
Jason Jeff Hebert / Flickr

What happens if you touch or swim in the Great Prismatic Spring?

The spring is the largest hot spring in Yellowstone National Park. Visitors are welcome to touch or swim in the water, but the water temperature in the spring can reach up to 160 degrees Fahrenheit. This can cause serious burns. Never step off the boardwalks.

Does the Grand Prismatic Spring smell?

Yes, it smells. The water from this type of underground spring has a high concentration of sulfur. The water also has a strong sulfur odor.

Where is Midway Geyser Basin?

The Midway Geyser Basin is located in Yellowstone National Park in the United States, just north of the Grand Loop Road.

The spring is situated in the Midway Geyser Basin, and is surrounded by a series of smaller springs and geysers. The area can be accessed by a short hike from the Fairy Falls Trail or by taking the boardwalk from the nearby parking area.

How to get to Midway Geyser Basin?

If you’re coming from the north, take the Grand Loop Road to Firehole Lake Drive. Turn left onto Firehole Lake Drive and follow it for about 1 mile until you reach the main area.

There is a parking area close to Midway Geyser Basin where you can leave your car. However, since it is a popular spot, the parking lot can be full, which is why you can see cars parked on the side of the road.

If you’re coming from the south, take the Grand Loop Road to Fairy Falls Trail. From there, follow the trail for about 1 mile until you reach there.

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