Most geysers in Yellowstone are like Steamboat — they do not erupt on regular schedules (Old Faithful is an exception). Certainly, the spate of activity was an exciting sight for the millions of visitors to Yellowstone National Park in 2018, and many tales of Steamboat eruptions graced social media this past summer.
The first Steamboat eruption of 2018 occurred on March 15. Following two additional eruptions in April and one on May 4, University of Utah and Yellowstone National Park scientists deployed seismic sensors around the geyser. The instruments recorded data through four eruptions before they were collected on June 4 (immediately following an eruption).
Steamboat wasn't the only Yellowstone geyser showing enhanced levels of activity in 2018. Giant geyser, in the Upper Geyser Basin (not far from Old Faithful), also erupted repeatedly (29 times, according to the GeyserTimes database). The last time Giant was so active was in 2007-2008, when it erupted several dozen times.
here was also a rare eruption of Ear Spring in the Upper Geyser Basin in September (an eruption that brought decades of human-generated garbage to the surface, like coins, a cinder block, and even a baby's pacifier), which was associated with the formation of a new thermal feature that forced the closure of a boardwalk. University of Utah scientists also responded to that event with a deployment of seismic sensors.
We don't know why intermittent geysers experience periods of heightened activity separated by months to years of dormancy or very infrequent eruptions. It is possible that the availability of water in the subsurface is a contributing factor — Yellowstone has experienced especially heavy precipitation in recent years.