Steamboat's major eruptions last from 3 to 40 minutes, 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.[4] 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.[5]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,[6] and is now classified as a hot spring.
The last eruption of Steamboat Geyser occurred on 3 September 2014.[7] The last ten major eruptions were on the following dates:[8]
October 2, 1991
May 2, 2000
April 26, 2002
September 13, 2002
March 26, 2003
April 27, 2003
October 22, 2003
May 23, 2005
July 31, 2013
September 3, 2014
Steamboat Geyser has two vents, a northern and a southern, approximately five meters apart.