Old Faithful is a cone geyser in Yellowstone National Park in Wyoming, United States. It was named in 1870 during the Washburn–Langford–Doane Expedition and was the first geyser in the park to be named. It is a highly predictable geothermal feature and has erupted every 44 minutes to two hours since 2000. The geyser and the nearby Old Faithful Inn are part of the Old Faithful Historic District.
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.
A mudpot, or mud pool, is a sort of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud. The acid and microorganisms decompose surrounding rock into clay and mud.
The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin.
The Firehole River is located in northwestern Wyoming, and is one of the two major tributaries of the Madison River. It flows north approximately 21 miles (34 km) from its source in Madison Lake on the Continental Divide to join the Gibbon River at Madison Junction in Yellowstone National Park. It is part of the Missouri River system.
Brilliant Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States. Brilliant Pool is part of the Daisy Group and is interconnected with the Daisy and Splendid Geysers. Prior to an eruption by Daisy or Splendid, the pool is filled.
Emerald Spring is a hot spring located in Norris Geyser Basin of Yellowstone National Park.
Fishing Cone, also known as Fishing Pot Hot Springs is a geyser in the West Thumb Geyser Basin of Yellowstone National Park in the United States.
Solitary Geyser is a fountain-type geyser in Yellowstone National Park, located above the Upper Geyser Basin. Eruptions last about a minute and are four to eight minutes apart; most eruptions are less than six feet in height. It is very distinctive with clear blue water underneath and a base that is tinted orange. Solitary Geyser is accessible via the Observation Point loop trail behind Old Faithful.
Black Pool is a hot spring in the West Thumb Geyser Basin of Yellowstone National Park in the United States.
Economic Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.
Morning Glory Pool is a hot spring in the Yellowstone Upper Geyser Basin of the United States. The spring is also known by the name Morning Glory Spring.
The following articles relate to the history, geography, geology, flora, fauna, structures and recreation in Yellowstone National Park.
Doublet Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park, Wyoming.
Chromatic Spring is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States.
Jewel Geyser is a fountain geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. It is in the Biscuit Basin complex that includes Black Diamond Pool, Black Opal Spring, Wall Pool, Sapphire Pool, Shell Spring, Silver Globe Spring, Avoca Spring, West Geyser, the Mustard Springs, Coral Geyser, and Black Pearl Geyser.
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.
Belgian Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park, Wyoming. Originally named Oyster Spring, it was renamed after a visitor from Belgium fell into it in 1929 with fatal results. The spring is less hot than other features in the area, at about 180 °F (82 °C), but still sufficiently hot for severe thermal burns. References to a "Belgian Geyser" in the 1930s may refer to this feature.
Ear Spring is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States. Located close to Old Faithful, on rare occasions Ear Spring will erupt as a geyser, and can shoot rocks and debris as well as water more than 25 feet (7.6 m) for a few minutes. On September 15, 2018, Ear Spring was seen on the National Park Service webcam at Old Faithful erupting for a minute and reached heights of 20 to 30 ft. This was the largest eruption the pool may have had since 1957. The eruption tossed small rocks out and the heated water killed the surrounding bacterial mats that normally thrive in less heated conditions. Likely related to the eruption of Ear Spring, a new thermal feature opened up under the pedestrian boardwalk near Pump Geyser which resulted in the National Park Service temporarily closing off the boardwalk. This new thermal feature was spouting water the night of September 18-19, 2018. Additionally, Doublet Pool and North Goggles Geyser have both been more active in the period immediately after the rare eruption of Ear Spring.
Black Sand Basin is one of a grouping of geothermal hot springs and geysers located in the Upper Geyser Basin of Yellowstone National Park, Wyoming. The spring is too hot to use as a mineral bath as its scalding 200 °F (93 °C) or hotter water has proven to be fatal. In the winter, a marked ski trail runs from the Old Faithful Visitor Center to Black Sand Basin
