File:Thermal image of Gray Bulger Geyser erupting (5 June 2016).jpg

English: The temperature scale is in degrees Fahrenheit.

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Geysers are hot springs that episodically erupt columns of water. They occur in few places on Earth. The highest concentration of geysers anywhere is in the Yellowstone Hotspot Volcano (northwestern Wyoming, USA).

Gray Bulger Geyser is a cluster of vents near the southern shore of Firehole Lake in the Black Warrior Group of Yellowstone’s Lower Geyser Basin. Over half a dozen active vents occur at & adjacent to the head of a somewhat J-shaped hot spring pool (vicinity of 44° 32’ 38.44” North latitude, 110° 47’ 04.01” West longitude). Some of these vents have been referred to as “Young Hopeful Geyser”, but Gryc (2016) demonstrated that Young Hopeful Geyser is a vent (now apparently inactive) just off the end of the hook of the J-shaped pool (at 44° 32’ 38.48” North latitude, 110° 47’ 04.22” West longitude). The most prominent erupting feature in the Gray Bulger Geyser complex is vent 3 of Gryc (2016). In 2014 and 2015, observed eruptions from vent 3 were two to four minutes long with intervals of six to eight minutes (“interval” = eruption start to eruption start).

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Reference cited:

Gryc, S. 2016 (dated 2015). Firehole Lake geyser delights (but which geyser is it?). Geyser Gazer Sput 29(6): 5-8.