Why Yellowstone’s Largest Active Geyser Isn’t Erupting With Normal Fury This Year

by Jennifer Shea

Geysers can be so unpredictable. While Yellowstone’s largest active geyser has been erupting quite a bit this year, its overall eruptions actually pale in comparison to recent years.

Steamboat Geyser in Yellowstone National Park is the world’s tallest geyser. And the geyser erupted yet again on Sept. 11, 2021. But it had gone 65 days without erupting before that, MTN News reports.

The Sept. 11 eruption put Steamboat at 14 major eruptions for this year. In 2018, it had 32 major eruptions. In 2019, it had 48. And in 2020, it had 48 yet again.

So the geyser’s current pace puts it on track to have a slower output than it did in recent years.

Yellowstone’s Steamboat Geyser Is Slowing Down

Steamboat reactivated in March of 2018 after sitting dormant for years. And from then until May of this year, it erupted every five to 10 days on average.

The eruptions, in which the geyser rockets mud, water, rocks and steam roughly 300 feet into the air, are a sight to behold. But park visitors have been getting fewer displays of the geyser’s might over recent months.

“Well, it looks like Steamboat’s slowing down,” Dr. Mike Poland, the scientist in charge at the Yellowstone Volcano Observatory, told MTN.

“This is one of those aspects of geysers,” Poland continued. “Most of them are really unpredictable, so you have to enjoy it while you can.”

The observatory head said scientists don’t know why Steamboat is now slowing down. Yellowstone’s top geyser has behaved entirely unpredictably.

“There’s no clear sign of what’s different now versus the way it was five years ago,” Poland said.

Scientists Have Some Inklings of How Geysers Work

Poland explained that scientists know a little bit about geysers’ underground plumbing networks. But that’s an area that’s tough to study because they have little visibility down there.

“One thing we do know is it has to have something to do with the sub-surface plumbing system, the geyser conduits,” he said of the geyser’s schedule of eruptions. “Whether or not they’re constricted or more open. And, that’s something that’s very difficult to understand because we just can’t see down there.”

As to why Steamboat sat dormant for 50 years before reactivating, Poland believes it has something to do with groundwater levels.

“I still feel like water availability has to have something to do with it,” he said. “Having high levels of groundwater, because there was a lot more rain and snow a few years ago than there has been the last couple of years.”

If Yellowstone’s top geyser goes dormant again, it will be disappointing for tourists, but exciting for scientists, who will have a chance to compare data from the recent years of eruptions to a dormant geyser.

Poland said they’ll be studying “precursory signals” to look for in the future. In the meantime, Yellowstone visitors should enjoy the active geyser while it lasts.