Driving through Yellowstone National Park, there is no cell phone signal. After all, you're deep in the wilderness. Until you get to the area around Old Faithful, Yellowstone's signature geyser. There, you can get a full five-bar signal, and as the geyser goes off, you can look around and see dozens of people explaining it live to friends via their phones.
That's because for many people, Yellowstone and Old Faithful are one and the same. But in fact, the park, America's first national park, is brimming with other geothermal delights. Whether it's other large geysers, deeply colored hot pools, hot springs, mud pots or steam vents, Yellowstone is a geothermal fan's best bet for being able to see the best of what nature has to offer, all in one place.
Here, the White Dome geyser goes off, as it does at irregular intervals. Many of the park's geysers go off on regular schedules, though Old Faithful--it's called that for a reason--may well be the most reliable.
One of the most impressive hot pools in Yellowstone is called the Morning Glory pool. It is famous for its deep colors and its otherworldly looks. But over the years, the pool has lost much of its color, according to reports--I wasn't able to visit Morning Glory Pool on Road Trip 2009--because of a wide variety of detritus thrown into it by park visitors.
This sign posted next to another beautiful hot pool is a warning--and an explanation--to visitors that they must not think of the pools the way they think of fountains. The junk gets stuck deep in the pools' pipes, clogging them and making it impossible for the pools to function as nature intended them to.
This is Silex Spring, on Yellowstone National Park's Fountain Paint Pot Trail.
According to the National Park Service, "Hot springs are the most common geothermal feature in Yellowstone. Their underground plumbing consists of unconstricted chambers of varying sizes. Water, which has been superheated far underground, rises along tiny cracks, flows into larger channels and eventually reaches the earth's surface.
"Unlike geysers, water convection is continuous within hot spring pools. Hot surface water sinks while hotter, superheated water continues to rise. This circulation keeps water below the temperature needed to begin the chain reaction leading to an eruption."
Along Yellowstone's Fountain Paint Pot Trail, visitors pass a gorgeous, but disturbing, feature called the Bacteria Mats.
This is actually a large collection of thermophiles--heat-loving microorganisms--that, according to the National Park Service, "usually form the ribbons of color like you see here. The green, brown and orange mats are mostly cyanobacteria, which can live in waters as hot as 167 degrees Fahrenheit."
A mud pot bubbles in the Artists Paint Pots area of Yellowstone National Park.
A mud pot, according to the National Park Service, is a hot spring "containing a relatively small amount of acid water. Acid breaks down the surrounding rock into clay, which mixes into the water. Mud consistency ranges from thick to thin, depending on the amount of water present. Abundant surface water in winter and spring thins the mud, creating a soupier mud pot. During the drier months of summer and autumn, mud pots often become thicker and sometimes dry up altogether."
A look at the placid Leather Pool, on Yellowstone's Fountain Paint Pot Trail. The pool "underwent dramatic changes after the Hebgen Lake Earthquake of 1959," reads a National Park Service brochure. "Prior to the earthquake, it was a warm (143 degrees Fahrenheit) pool that supported leather-like thermophilic brown bacteria. After the earthquake, water temperatures rose to boiling and killed the microorganisms. Since that time, Leather Pool has cooled and again supports the brown bacteria."
Another relic of the 1959 Hegben Lake Earthquake, Red Spouter, which was created as a result of the quake, "exhibits the behavior of all four thermal features (mud pot, geyser, hot spring and steam vent)," reads a National Park Service brochure. "In the spring and early summer, its pools splash muddy water that sometimes has a red tone. Later in the summer and fall, when the water table is lower, Red Spouter becomes a hissing fumarole (which produces hissing and steaming from gases--hydrogen sulfide, carbon dioxide and steam). And some people say it has erupted in the past."
One of the geothermal attractions along the Firehole Lake Drive, Great Fountain Geyser can produce eruptions--which occur about every 10 to 14 hours and which last at least 45 minutes--measuring 100 feet, and even sometimes, 200 feet.
"Geysers are hot springs that periodically eject boiling water and steam into the air," reads a National Park Service sign. "Most geysers are unpredictable. Some, like Old Faithful, display patterns of activity...A narrow zone, or constriction, and boiling water are necessary for a hot spring to erupt as a geyser. The constriction keeps water within the system from circulating to the surface for cooling. Eruptions occur as a chain reaction: Water, held within the geyser's plumbing, becomes superheated--heated beyond boiling--and rapidly expands in volume as it changes into steam; then steam bubbles force themselves--and the water above--past the constriction and up into the air."
The namesake of Firehole Lake Drive, Firehold Spring is a beautiful spring that convinced early explorers to think that "the larger bubbles looked like flashes of light--hence the origin of the spring's name," reads a National Park Service brochure.