What Is Old Faithful?

Wyoming's Yellowstone National Park is home to a number of incredible natural wonders, including the well-known geyser Old Faithful. One of many geysers found within Yellowstone National Park, Old Faithful was originally named in 1870 by the Washburn-Langford-Doane Expedition. The members of the expedition referred to the geyser as "Old Faithful" in large part because its eruptions were so regular and predictable.

Geysers are rather rare geological occurrences. A geyser is essentially a water spring which forcefully ejects water from an opening in the earth, as well as releases steam or vapor on a regular basis. Precise hydrogeological conditions must exist in order for a geyser to form — conditions which are usually only found near active volcanoes due to the presence of magma. Yellowstone National Park is one such site and is, in fact, home to nearly half the geysers found throughout the world.

Although there are a number of other geysers found in Yellowstone National Park, some of which are actually taller or erupt more frequently, Old Faithful is generally regarded as the most famous. One reason for the attraction to Old Faithful is the regularity and predictability of its eruptions. The regularity of eruptions is due in large part to the fact that Old Faithful is not interconnected with any other thermal features of the geyser basin.

For visitors who wish to view an Old Faithful eruption, he or she will typically not need to wait more than 90 minutes. The interval at which eruptions occur depends on the duration of the last eruption. The shorter the last eruption was, the less time a visitor will need to wait until the next eruption. For example, if the last eruption lasted for two minutes, then the next eruption occurs in approximately 57 minutes; however, if the last eruption lasted five minutes, then a visitor will have to wait closer to 95 minutes for the next spew.

Eruptions from Old Faithful can reach heights of up to 185 feet (56 meters) with internal temperatures climbing to nearly 200° Fahrenheit (93° Celsius). The water is so hot and forceful that visitors and nearby residents used to use the geyser as a way to wash their laundry! Today, of course, visitors are not allowed to get close enough to wash their laundry, but are allowed to view the eruptions from park benches stationed 300 feet (91 meters) away from the opening of the geyser.