Yellowstone is the place to see geysers. Home to about half of the world’s geysers—the largest concentration on earth—Yellowstone delivers big-time when it comes to providing visitors with front-row views of these dramatic, steaming vents and spouting columns of superheated water. Yellowstone contains more than 10,000 geothermal features in the form of hot springs, travertine terraces, geysers, mud pots, and fumaroles. Here’s where to find the best Yellowstone has to offer.
Upper Geyser Basin contains the world’s greatest concentration of hot springs.
Set between the Old Faithful area and Biscuit Basin road, the Upper Geyser Basin contains several groups of hot springs, as well as more than 150 geysers. The basin is less than a half-mile wide, and most of its features are in close proximity of the Firehole River.
Plan to spend at least half a day exploring the area, which is home to the park’s most impressive and well-known geysers, including:
The most famous geyser in the world—Old Faithful. It was discovered in 1870 by the Washburn Expedition, whose members stumbled upon the geyser during an eruption. One can imagine what it must have been like for those early explorers to see Old Faithful in all its glory. Even today, seeing Old Faithful erupt is an unforgettable experience.
On average, Old Faithful erupts about every 92 minutes, and shoots water 135 feet into the air, but has been known to erupt as high as 190 feet.
“When will Old Faithful erupt next?” is probably the most common question heard by interpretive rangers working in the Upper Geyser Basin, and to help answer that question a table of estimated times is posted near the geyser. In order to predict an eruption, observers analyze past information such as intervals between eruptions, and the length and character of previous eruptions.
Castle Geyser is interesting because it accumulates so much energy. After about 15 minutes, Castle goes into a raucous steam phase and roars like a train. Castle erupts from a 30-foot-tall cone—one of the largest in the Upper Geyser Basin—and averages about 11 to 13 hours between eruptions, with bursts that shoot 70 to 80 feet into the air.
Riverside Geyser is unique in that it shoots water about 80 feet into the air at a 60-degree angle across the Firehole River. Visit this geyser in the afternoon and you may even see a rainbow in the steamy mist. It erupts about every six hours for roughly 20 minutes.
Midway Geyser Basin is located “midway” between Yellowstone’s Upper and Lower geyser basins, and covers a one-mile stretch along the Firehole River. Although relatively small compared to the park’s other geothermal areas, Midway Geyser Basin is home to some impressive hot springs, including Grand Prismatic Spring, Yellowstone’s largest single hot spring and the world’s third largest hot spring.
This enormous pool is not only huge, but colorful, too, as rising steam reflects the colors of the rainbow in an impressive display.
Lower Geyser Basin, located between Madison Junction and Upper Geyser Basin, contains nearly 100 geothermal features— including fumaroles, hot springs, geysers and mud pots. Acidity in the steam is responsible for the surface rock in this area breaking into clay. Clay and steam pushing through the rock have created the most popular attraction in the basin, the Fountain Paint Pots, which are Yellowstone’s most easily accessible large group of mud pots. The steam responsible for the paint pots colors the clay with shades of white, brown and gray. Additional liquid at different times of the year gives the paint pots their characteristic look of bubbling, blended mud.
Norris Geyser Basin is Yellowstone’s hottest and oldest thermal area. Many geyser aficionados also feel that Norris is the most exciting and unpredictable of the various basins in Yellowstone.
Two very different basins make up Norris Geyser Basin: Porcelain Basin and Back Basin. Back Basin has impressive geysers like Echinus Geyser, while Porcelain Basin is home to many hot springs, vents and pools. Steam vents are often referred to as fumaroles. A fumarole is like a hot spring, but with less water and a lot more heat. They are so hot that what little water there is boils away before reaching the surface. The result is a hissing steam vent, such as Norris’ Black Growler Steam Vent.
The Mud Volcano area, just north of Yellowstone Lake, includes more than a dozen unique geothermal features.
Visitors will no doubt notice a “rotten egg” odor when visiting Mud Volcano. This is the result of microorganisms eating away at sulfur, which creates sulfuric acid. As it evaporates, the acid becomes hydrogen sulfide gas, which gives off the noxious smell.
Dragon’s Mouth Spring is this area’s most popular feature. This is a spring that fills a cave in the side of a hill. The gases that rise to the surface cause the water to splash back and forth against the three cave walls. This splashing of water resembles a tongue lashing out, and gives the spring its name.
Mammoth Hot Springs, in the northwest section of the park, features an array of travertine terraces. The terraces are created when hot water and gases ascend through limestone deposits, “sculpting” the rock along the way. Once exposed to the air, some of the carbon dioxide escapes and calcium carbonate from the limestone is deposited as a rock called travertine. Flowing water spills over the colorfully streaked terraces, resulting in gentle cascades.