Yellowstone National Park

Geyser Basins
Old Faithful, Yellowstone National Park
Old Faithful, Yellowstone National Park (Photodisc/Getty)

"...and behold! The whole country beyond was smoking with the vapor from boiling springs, and burning with gasses, issuing from small craters, each of which was emitting a sharp whistling sound." - from The Yellowstone Story by Aubrey L. Haines

One of Earth's Most Extreme Environments

If you want to see the hottest, most changeable thermal area in Yellowstone, visit the Norris Geyser Basin. With approximately 2.25 miles of trails, this site offers the world's tallest active geyser, colorful hot springs, and the opportunity to see microscopic life in one of the most extreme environments on earth.

The Norris Soldier Station remains a link to Yellowstone's past: The area originated as a U.S. Army outpost. The Army administered Yellowstone National Park from 1886 to 1916, and the Soldier Station is a relic of that era. Today, it houses the Museum of the National Park Ranger. Museum exhibits highlight details of the evolution of the ranger profession from its roots in the military to the modern specialist.

Indisputably, thermal features are fragile rarities of nature. Yellowstone preserves the largest natural geothermal area on the planet—affording an unparalleled opportunity to view hot springs, geysers, mud pots, and steam vents in a natural setting. People can disrupt the geyser basin's natural process of change—causing irreparable damage. Rocks, sticks, and other objects thrown into a geyser's or hot spring's vent may be permanently cemented in place, choking off water circulation and ending all activity. At Norris, Ebony Geyser in Porcelain Basin and Minute Geyser in Back Basin have been victims of this thoughtless destruction.

Fascinating Legends, Colorful History

Trapper Joe Meek stumbled upon the Norris area in 1829. The mountain man was so astounded by what he discovered in this wild, rugged country that he carried the story with him the rest of his life. The legend of a land of fire and brimstone was born from the yarns of wanderers such as Joe.

Although the Norris area was formally explored in 1872, it was Yellowstone's second superintendent, Philetus W. Norris (1877-1882), who provided the first detailed information about the geysers and hot springs. A self-taught historian, archeologist and scientist, Norris made great strides in documenting the park's natural and human history.

He also constructed the first roads to some of the park's major attractions, erected the first government buildings, and made recommendations that led to the development of the first Federal-run game management program. His questing nature led him to explore the vast Yellowstone wilderness, and he named many landmarks for himself. Today, Norris Geyser Basin is the best known of the features that bare the name of this park pioneer.

During the Army era of park administration (1886-1916), Fort Yellowstone in Mammoth Hot Springs was the headquarters for a series of outposts from which soldiers performed the daily tasks of protecting the park. By 1916, detachments were stationed in 16 places. These became ranger stations in the early years of National Park Service administration.

The Norris Soldier Station (located just inside the entrance to the present Norris Campground) was among the longest occupied stations in the park. The first structure, built in 1886, was replaced in 1897 and modified again in 1908, remaining essentially unchanged thereafter. Life at the outpost was rugged and isolated, and, at times, even dangerous. After the Army years, Norris Soldier Station was a ranger station until an earthquake in 1959 rendered the structure unsafe. The building was restored in 1991 and now houses the Museum of the National Park Ranger. Museum exhibits tell the story of the evolution of the park ranger from soldier to modern specialist.

When the National Park Service took over the management of Yellowstone in 1916, many of its earliest policies were based on precedents established by the Army. However, the creation of an education program to interpret the wonders of the park to its visitors was a significant new development in park management. Trailside museums were the first facilities designed to provide information and exhibits at some of the major attractions. The Norris Geyser Basin Museum, one of the park's original trailside museums, opened to the public in 1930. Its rustic appearance is an excellent example of the stone and log architecture of the period.

Today, the wilderness setting, extraordinary geothermal features, and relics of a colorful history make Norris a fascinating area to explore. Ranger-naturalist activities can further enrich your visit. Ask at the Museum of the National Park Ranger or the Norris Geyser Basin Museum for more information.

Norris Geyser Basin

Hot, hot, hot!
Nowhere else can you find the diversity and changeability that occurs at Norris. And keep in mind that the highest temperature yet recorded in any geothermal area in Yellowstone was measured in a scientific drill hole at Norris: 459º F, just 1,087 feet below the surface! Most springs and all geysers here are hot enough to release boiling water.

The oldest of Yellowstone's active geyser basins, Norris' hot spring waters (mostly originating as rain and snowmelt), have flowed here for over 115,000 years. But there are many other unique features to this area.

Mysterious Forces
Some of the world's most extreme volcanic explosions have occurred at Central Yellowstone. Indeed, geysers, hot springs, mud pots, and steam vents can just hint at the powerful and mysterious forces of volcanism. From several vantage points around the park, it is possible to view the outline of an immense crater (caldera) created approximately 600,000 years ago, the time of the last major volcanic explosion. Scientists believe that a partially molten chamber of rock remains beneath Yellowstone.

Norris is at the junction of several disturbances in the earth's crust. A major fault (rock fracture) runs south from the Mammoth Hot Springs area toward Norris. This fault crosses another fault extending eastward from Hebgen Lake to Norris. Both of these breaks in the earth's surface intersect with fractures radiating from the great caldera that dominates central Yellowstone.

Water from rain and snowfall percolates downward through cracks and fissures and becomes heated, rising to the surface again as a hot spring, geyser, mud pot, or steam vent. At Norris, a rare combination of ingredients creates a landscape unique on this planet.

Each year at Norris a few new hot springs and geysers appear while others become dormant. A steam vent may evolve into a hot spring, a hot spring might begin erupting, or a geyser's pattern of eruption might suddenly change. Geologic events or processes cause many of the observable changes in thermal activity.

Hundreds and sometimes thousands of earthquakes and tremors are recorded annually at Yellowstone. Most are too small to be felt but all are capable of triggering subtle as well as dramatic transformations in thermal behavior. Whether these changes will be long lasting or just a brief variation in each feature's "normal" activity is something that can only be determined over time. Geysers and hot springs may also create changes in themselves. Some Norris springs, like Cistern, dissolve rock at depth at a tremendous rate. This dissolved rock is redeposited along subterranean passageways as very hot water moves toward the surface. Additional deposits accumulate around the surface vents. If deposition continues, a geyser or hot spring may seal itself shut, choking off its flow of water. In turn, new features may be born as this hot, pressurized water seeks release. The flow may also find its way into nearby features, causing changes in their behavior.

Thriving The overflow channels of geysers and hot springs are often brightly colored with minerals and microscopic life forms. Many of Norris's features, such as Echinus Geyser and Green Dragon Spring, release acidic water. Hardy microscopic plants, like lime-green Cyanidium algae, thrive in these warm acid waters. Orangish cyanobacteria may be found in many runoff streams in Porcelain Basin; from a distance these bacteria look like rusty iron-rich mineral deposits.

Amazingly, living organisms thrive even in the extreme environments of Norris's acid hot springs! These and other microscopic life forms are links to the emergence of life on earth billions of years ago. They are also contributing to cutting-edge research in the fields of medicine and criminal investigation, yielding new tools in such complex areas as AIDS research and DNA "fingerprinting."

At Norris, widespread "disturbances" of geothermal activity take place in a cyclic, almost predictable pattern. No other thermal area in Yellowstone exhibits this phenomenon; something unique to the Norris area is responsible for this transformation.

Mysteriously, toward the end of summer or early autumn (with a few exceptions over the years), features throughout the Norris area undergo dramatic behavioral changes literally overnight! Clear pools become muddy and boil violently, and some temporarily become geysers.

Features that typically behave as geysers may display altered eruption cycles or temporarily cease erupting. New features have been created during a disturbance although they seldom remain long-term attractions in the basin. Disturbances tend to last from a few days to more than a week. Gradually, most features revert to "normal" activity.

Why this happens is not fully understood. Features here may be served by multiple geothermal plumbing systems at varying depths. The lack of extensive sinter buildup around surface vents may allow more recycling of hot water into the shallow portions of the plumbing system. Further study will no doubt yield new clues that will help unravel the mystery of this phenomenon and lead to a greater understanding of the earth's hidden geologic forces.

Windows to the Earth's Interior: Geyser Basin

Originating as rain or snow, water falls to the earth's surface and seeps down through porous rock layers. Eventually it comes into contact with rocks heated by the magma body laying beneath Yellowstone. This superheated water rises back toward the surface through cracks and fissures, collecting into larger channels that serve as the "plumbing" for each thermal feature. If the plumbing channel contains a constriction, the superheated pressurized water flashes into steam, forcing the water above it out and up as a geyser eruption.

Hot springs are features with no plumbing constriction. Superheated water cools slightly as it reaches the surface, to be replaced by hotter water from deeper sources. This sets up a pattern of water circulation or convection, and the temperature required to set off the chain reaction leading to an eruption is never quite reached.

Fumaroles (steam vents) are hot springs without enough water to flow. Thus steam pours forth, sometimes as gentle puffs and sometimes as powerful blasts.

Mud pots form when acid decomposes or breaks down surrounding rock into clay. This clay mixes with water to form mud of varying consistency and color.

Back Basin

Emerald Spring
In Emerald Spring, the blue of clear water combines with the yellow of the sulfur-coated crater to create a magnificent green color. The temperature of this 27 foot (8 m) deep pool is usually within the 190º F (89º C) range. The boiling point at Norris is 199º F (93º C).

Steamboat Geyser
The world's tallest active geyser, Steamboat can erupt to over 300 feet (90 m), showering viewers with its mineral-rich waters. For hours following its rare 3-40-minute major eruptions, Steamboat thunders with powerful jets of steam. As befitting for such an awesome event, full eruptions are entirely unpredictable. Recently, Steamboat had one major eruption in 1990, one in 1991, but none between 1992 and 1995.

More commonly, Steamboat ejects water in frequent bursts of 10 to 40 feet. Consult the display in the Norris Geyser Basin Museum for updates.

Cistern Spring
Cistern Spring and Steamboat Geyser are linked underground. During a major eruption of Steamboat, the water in Cistern Spring's pool drains. Normally, Cistern is a beautiful blue pool from which water continually overflows. It is quite creative, depositing as much as 1/2 inch (12 mm) of grayish sinter each year. By comparison, Old Faithful Geyser and other adjacent thermal features may build deposits at the rate of 1/2 to 1 inch (12-25 mm) per century. Cistern Spring's influence expands throughout the lodgepole pine forest below; this forest has been slowly flooded with silica-rich water since 1965. The pioneering lodgepole forest at Norris is in constant flux, retreating here and in other areas of increasing heat while advancing in places of diminished thermal activity.

Echinus Geyser
A perennial crowd-pleaser, Echinus typically erupts regularly every 35-75 minutes. Its pool fills gradually with water; then suddenly, bursts of steam and water explode 40-60 feet (12-18 m) skyward. Eruptions usually last 6-14 minutes but may last 60 minutes or longer. Echinus is the largest acid-water geyser known; its waters are almost as acidic as vinegar (pH 3.3-3.6). Acid geysers are extremely rare; the majority of our planet's total are found here in the Norris Geyser Basin!

Green Dragon
Except on warm summer afternoons, steam frequently fills the cavern of this intriguing hot spring. Wait patiently for a glimpse of the sulfur-lined cave and boiling green water.

Porkchop Geyser
Dramatic behavioral changes have characterized Porkchop Geyser during the last decade. Once a small hot spring that occasionally erupted, Porkchop Geyser became a continuous spouter in the spring of 1985. The force of the spray caused a roar that could often be heard at the museum. On September 5, 1989, Porkchop Geyser exploded. Rocks surrounding the old vent were upended; some were thrown more than 216 feet (66 m) from the feature. Porkchop Geyser is now a gently boiling hot spring.

Minute Geyser
Once one of the major geysers at Norris, Minute Geyser now spouts about 1 foot (0.3 m) above its crater. Vandals plugged the geyser's plumbing, drastically altering its behavior. No one can predict if Minute Geyser will ever again display its former powerful eruptions.

Thermal activity may change by the time you arrive at Yellowstone National park. For updates, ask rangers on duty in the area or inquire at park visitor centers.

Porcelain Basin

Norris Museum Overlook
Rainbow colors, hissing steam, and pungent odors combine to create a vista unique in Yellowstone. Porcelain Basin is open with hundreds of densely packed geothermal features in contrast to the more forested terrain of Back Basin, where features are more scattered and isolated.

Porcelain Terrace Overlook
Parts of the whitish rock sheet before you pulsate from the pressure of steam and boiling water beneath them. A number of geysers and other features here have been born suddenly in small hydrothermal explosions. Some features are ephemeral, their activity lasting a few hours, days, or weeks. However, some, like Blue Geyser, have become relatively "permanent" fixtures in the scene.

Due to their saturation with opalescent silica minerals or clay, many of these pools have a milky coloration. Some pools have orange-rimmed edges; iron in combination with other elements, such as arsenic, is responsible for the color.

Additional Geyser Resources

Here are some interesting materials that can further your knowledge of the Geyser:

Guide to Geyser Gazing, Dr. John S. Rinehart
Geologic Map of Yellowstone National Park, Montana State University
Life at High Temperatures, Dr. Thomas Brock
The Geysers of Yellowstone, T. Scott Bryan
Geysers: What They Are and How They Work, T. Scott Bryan
Roadside Geology of the Yellowstone Country, William J. Fritz
Geysers of Yellowstone videotape, Finley Holiday Films
Yellowstone: Imprints of Geologic Time videotape, Terra Productions
Yellowstone Place Names, Lee Whittlesey
A Field Trip Guide to Yellowstone National Park, U.S. Geological

These publications are sold by the Yellowstone Association at the Norris Bookstore and in visitor centers throughout the park.


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