Yellowstone's Steamboat geyser is the world’s tallest currently active geyser and it has been really active lately. In 2019, it counted 48 eruptions, according to the USGS Yellowstone Volcano Observatory. This number by far surpassed the previous record set in 2018 of 32 eruptions.
The last time the geyser was remotely this active was in 1964, when it counted 29 eruptions. Records published on the National Park Service website go back as far as 1878, also showing that the geyser has in the past gone years without erupting even a single time.
A geyser is a vent through which hot water and steam from below the Earth’s surface can erupt. According to geology.com, geysers are extremely rare phenomena that only occur when many conditions are met. As a result there are only about 1000 geysers in the world. Generally, a geyser forms if water accumulates underground in the proximity of magma, is heated up quickly and ejected onto the surface as steam.