Mugwump Geyser eruption (7:37-7:38 PM, 5 June 2018) 3
Geysers are hot springs that episodically erupt columns of water. They occur in few places on Earth. The highest concentration of geysers anywhere is at the Yellowstone Hotspot Volcano (northwestern Wyoming, USA).
Mugwump Geyser is located in the northern part of the Three Sisters Spring complex. The complex consists of a single, moderately large, continuous pool that is 39 meters along its long axis and is 14 meters across at its widest. Seven major vents are present: South Sister Spring, Middle Sister Spring, North Sister Spring, Mugwump Geyser, Three Crater Geyser, Little Brother Geyser, and an unnamed geyser having the catalog designation "UNNG-MYR-1".
Mugwump Geyser is located between UNNG-MYR-1 and North Sister Spring. It is rarely active. For many years, Mugwump Geyser was quiet and had greenish-colored water. In 2016, Mugwump Geyser had bluish-colored water and was having eruptions. Intervals (= eruption start to eruption start) are about 15 minutes, but range from 9 to 31 minutes. Eruptions typically consist of two "bursts" involving about 5 to 10 seconds of erupting water with subterranean thumping, followed by a less-than-one-minute pause, and then another 5 to 10 seconds of eruption with thumping. Some Mugwump eruptions are one or three bursts. Eruption heights vary but the largest reach about 30 feet high.
Mugwump Geyser was still having eruptions in late January 2017. In late April 2017, the geyser was reported to be dormant, with dry runoff channels, cooler water temperature, and some orangish-colored microbial growth. Mugwump continued to be dormant until mid-August 2017, with witnessed eruptions being reported. Regular eruptions from Mugwump continued in April and June 2018.