| one of the best known geysers of Yellowstone National Park. |
| Old Faithful A geyser in Yellowstone National Park in northwest Wyoming. Its eruptions, which last about 4 minutes, occur on the average of once every 65 minutes (the intervals can vary from 33 to 90 minutes). The geyser sends up a column of hot water and steam ranging from 35.4 to 53.4 m (116 to 175 ft) high. |
Old Faithful
most famous, though not the highest, of all North American geysers, at the head of the Upper Geyser Basin in Yellowstone National Park, Wyoming, U.S. It was so named in 1870 by the Washburn-Langford-Doane Expedition because it seemed to spout "faithfully" every 63-70 minutes. Under continuous observation, however, it has been found that the eruptions occur with some irregularity, with intervals varying from 33 to 120 minutes. After the 1983 Borah Peak (Idaho) earthquake, these intervals became increasingly less predictable. The duration of Old Faithful's eruptions ranges from 1.5 to 5.5 minutes. Billowing steam and from 3,700 to 8,400 gallons (14,000 to 32,000 litres) of hot water are ejected at one eruption. The geyser's fountainlike columns reach heights of about 170 feet (52 metres) on calm, windless days.
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