Steamboat Geyser, in Yellowstone National Park’s Norris Geyser Basin, is the world's tallest currently-active geyser. During major eruptions, water may be thrown more than 300 feet (90 m) into the air.
Steamboat's major eruptions last from 3 to 40 minutes in length, and are followed by powerful jets of steam. Steamboat does not erupt on a predictable schedule with recorded intervals between major eruptions ranging from four days to fifty years. The geyser was dormant from 1911 to 1961. Minor eruptions of 10 to 15 feet (3–5 m) are much more frequent. After an eruption the geyser often vents large amounts of steam for up to 48 hours.Cistern Spring, located nearby, will drain completely during a major eruption of the geyser; the spring refills within a few days.
Prior to 1904, Waimangu Geyser, in New Zealand, had some taller eruptions capable of reaching 1,600 feet (490 m) but in 1904 a landslide changed the local water table and since then Waimangu has not erupted.Excelsior Geyser in Yellowstone's Midway Geyser Basin likewise was taller, with eruptions reaching 300 feet (91 m). However, Excelsior has not erupted since 1985,and is now classified as a hot spring.
As of 23 May 2005, the last eight eruptions of Steamboat Geyser occurred on:
- 12 October 1991
- 2 May 2000
- 26 April 2002
- 13 September 2002
- 26 March 2003
- 27 April 2003
- 22 October 2003
- 23 May 2005
Steamboat Geyser has two vents, a northern and a southern, approximately five meters apart.