A geyser is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only in a few places on Earth.
The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at 10,000. A study that was completed in 2011 found that a total of 1,283 geysers have erupted in Yellowstone, 465 of which are active during an average year. These are distributed among nine geyser basins, with a few geysers found in smaller thermal areas throughout the Park. The number of geysers in each geyser basin are as follows: Upper Geyser Basin (410), Midway Geyser Basin (59), Lower Geyser Basin (283), Norris Geyser Basin (193), West Thumb Geyser Basin (84), Gibbon Geyser Basin (24), Lone Star Geyser Basin (21), Shoshone Geyser Basin (107), Heart Lake Geyser Basin (69), other areas (33). Although famous large geysers like Old Faithful are part of the total, most of Yellowstone's geysers are small, erupting to only a foot or two. The hydrothermal system that supplies the geysers with hot water sits within an ancient active caldera. Many of the thermal features in Yellowstone build up sinter, geyserite, or travertine deposits around and within them.
Grand Geyser is a fountain geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. It is the tallest predictable geyser known. It was named by Ferdinand Vandeveer Hayden in 1871.
The Fountain Paint Pot is a mud pot located in Lower Geyser Basin in Yellowstone National Park.
Anemone Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. Anemone is actually two closely related geysers. The larger of the two is known as Big or North Anemone while the smaller is known as Little or South Anemone. The two geysers were named after the anemone flower by the Hague Party in 1904. Both vents have a pale yellow color and shape similar to the flower.
A-0 Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the United States.
Spindle Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the U.S. state of Wyoming.
Artemisia Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.
Labial Geyser is a fountain-type geyser in the Lower Geyser Basin of Yellowstone National Park in the United States. It is part of the Pink Cone Group. Other geysers in this groups are Labial's Satellite Geyser, Bead Geyser, Box Spring, Dilemma Geyser, Narcissus Geyser, Pink Geyser, and Pink Cone Geyser.
Pink Geyser is a fountain-type geyser in the Lower Geyser Basin of Yellowstone National Park in the United States.
Excelsior Geyser Crater, formerly known as Excelsior Geyser, is a dormant fountain-type geyser in the Midway Geyser Basin of Yellowstone National Park in the United States. Excelsior was named by the Hayden Geological Survey of 1871.
Fountain Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the United States.
The Great Fountain Geyser is a fountain-type geyser located in the Firehole Lake area of Lower Geyser Basin of Yellowstone National Park, Wyoming. It is the only Lower Geyser Basin feature that the park makes predictions for.
Jet Geyser is a geyser in the Lower Geyser Basin of Yellowstone National Park in the United States. Jet Geyser is in the Fountain Group that includes Fountain Geyser, Morning Geyser, Red Spouter and Silex Spring.
Grotto Geyser is a fountain-type geyser located in the Upper Geyser Basin in Yellowstone National Park in the United States. Grotto Geyser is the namesake for the group of geysers that includes Grotto Fountain Geyser, South Grotto Fountain Geyser, Indicator Spring, Spa Geyser, Startling Geyser, and Rocket Geyser.
White Dome Geyser is a geyser located in the Lower Geyser Basin in Yellowstone National Park in the United States.
Giantess Geyser is a fountain-type geyser in the Upper Geyser Basin of Yellowstone National Park. It is known for its violent and infrequent eruptions of multiple water bursts that reach from 100 to 200 feet. Eruptions generally occur 2 to 6 times a year. The surrounding area may shake from underground steam explosions just before the initial water and/or steam eruptions. Eruptions may occur twice hourly, experience a tremendous steam phase, and continue activity for 4 to 48 hours. The Geyser last erupted on August 26, 2020 after a six year, 210 day hiatus. A follow-up eruption occurred 15 days later on 10 September 2020. Another eruption occurred on 11 August 2021
Sawmill Geyser, named for the whirring sound it makes during its eruption, is a geyser in Yellowstone National Park, Wyoming, United States. The geyser was named by Antoine Schoenborn of the Hayden Geological Survey of 1871.
Opal Pool is a hot spring in the Midway Geyser Basin of Yellowstone National Park, Wyoming. Opal Pool usually has a temperature of approximately 132 °F (56 °C). Though usually active as a hot spring, Opal Pool is considered a fountain-type geyser.
Morning Geyser is a fountain-type geyser located in the Fountain Paint Pots area of Lower Geyser Basin of Yellowstone National Park, Wyoming. When active it is the largest geyser in the Fountain Paint Pots area, but in most years it is inactive.
