Named after Philetus W. Norris, second superintendent of Yellowstone National Park (1877-1882), Norris Geyser Basin is an active, changing, and often unpredictable hydrothermal region. The area is divided into the Porcelain Basin and the larger Back Basin. Both basins contain a variety of hydrothermal features including majestic geysers, colorful hot springs, plopping mudpots, and noisy fumaroles. The Porcelain Basin has an overlook that allows you to see most of this basin’s geothermal features. Steamboat Geyser, located in the Back Basin, is the world’s tallest active geyser, shooting water more than 300 feet (91 m) high during major eruptions, though they are quite infrequent. However, recent years have seen an unusual high number of major eruptions. The variety and high concentrations of hydrothermal features in the basin is certainly worth a stop to explore. The area has multiple trails that are a combination of boardwalk, stairs, and ground. While parts are wheelchair accessible, areas would require assistance as the changing terrain can make certain places difficult to navigate. A 1-mile paved and level trail connects Norris Campground and the geyser basin.
 

There is parking for cars and separate parking for RV’s and buses. Finding a spot on crowded days can be tricky. Amenities include three duel restrooms, all located at or near the parking lots and have vending machines located outside. A small informational museum and bookstore welcome you to the entrance to the basin.

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The Hydrothermal Features of Norris Geyser Basin: Beneath the park, partially molten rock called magma heats water that permeates down from the surface through faults and fractures. This superheated water rises back towards the surface and collects into large channels, dubbed the “plumbing” for the hydrothermal features. From here the superheated water escapes to the surface through:
 

• Geysers are formed when a constriction in the plumbing channel causes a buildup of the water temperature and pressure. Steam forms and eventually produces a forceful upward expulsion of water through the constricted area and the geyser erupts.
   

• Hot Springs are superheated water in plumbing channels that do not have a constricted area and therefore bubble to the surface in a pattern of water cycling or circulation without the periodic increases in pressure that would lead to an eruption.
   

• Mudpots are the result of acid that breaks down surrounding rock into clay and mixes with water forming the mud. The characteristic “plopping” seen in the mudpots is caused by escaping gases that burst through the mud to the surface.
   

• Fumaroles are also known as steam vents, form when the underground channels penetrate hot rock. With relatively little water that drains into these features, it is instantly converted to steam that is forced upward out of the vents.
   

The various colors that are found in the hydrothermal pools and drainage areas are the result of thermophiles, microorganisms that thrive in an environment of heat and acidity or alkalinity. The color that is present reflects the dominant type of thermophile concentrated in an area and/or the energy source for the microorganism. Scientists believe the first organisms on earth were thermophiles and use Yellowstone examples as analogs . . .
 

• Dark brown, rust, and red mats contain varying amounts of iron that certain bacteria metabolize.
   

• Emerald-green runoff channel mats form when algae that contain chlorophyll, a green pigment that helps convert sunlight to energy, dominate the area.
   

• Yellow deposits contain concentrations of sulfur that some thermophiles use for energy. Sometimes this forms sulfide gas that gives off a rotten egg odor. They form colonies of mats that look like clumps of hair waving in the water.
   

• Dark blackish-green mats form in water that is typically cooler, and an alga forms a community.