Steamboat Geyser, the tallest active geyser in the world, erupted more times in 2019 than in any other year, baffling scientists who are trying to understand what triggered this unusual streak of activity.
The geyser can shoot water more than 300 feet into the air, and this year it has erupted more than 45 times, surpassing the 32 eruptions recorded in 2018.
"In the 1960s, there was another period where there were more than 20 eruptions per year," says Erin White, Yellowstone National Park's hydrologist. "Prior to that, there were dormant periods of more than 50 years."
She has stood right next to Steamboat as it was venting steam. "It is incredibly powerful," White says. "It's like standing next to a jet engine."
Steamboat's reawakening is an opportunity for researchers to try to answer some fundamental questions about how geysers work.
"It's such a big geyser. And the bigger something is, the easier it is to study," says Michael Manga of the University of California, Berkeley. "But it also captures people's imagination. When it got active again there was lots of press and it reminded people that there are fundamental things about the Earth we don't understand."
Geysers are relatively rare — the planet has fewer than 1,000, and about half of them are in Yellowstone.
And not many people study these erupting hot springs. The geyser scientific community "is a community of almost nobody," Manga says.
A couple of years ago, when he and a colleague wrote a review of geyser research for a science journal, "we could cite just about every paper ever written about geysers. And there's very few fields where you can do that."
Researchers do know the basic ingredients needed for a geyser, White says.
"You need to have a source of water, you need a source of heat, and you need a structure, a geologic structure, that is constrained or confined in some way to develop pressure that will generate an eruption," she says.
Yellowstone is a seismically active place, and it's possible that the reactivation of Steamboat was somehow related to the Maple Creek earthquake swarm in 2017, says Yellowstone National Park geologist Jeff Hungerford.
"Steamboat is in the Norris geyser basin, and the Norris geyser basin is a really dynamic area. It's one of the hottest areas of the park and it's also one area in the park where we see focused deformation, or swelling of the ground, where the ground actually uplifts and subsides," Hungerford says.
All of that might have created channels for fluids to move around underground. But researchers do not have detailed maps of what's going on beneath Steamboat.
"What is the subsurface architecture?" White wonders. "What is the volume of water that is available for every eruption?"
"People always ask, 'Well, why is steamboat such a tall geyser?' We can't answer that question," Manga adds.
Scientists do have temperature sensors deployed around the geyser. And there have been recent studies using arrays of seismic sensors. It appears that Steamboat's liquid is stored at depths of about 65 to 130 feet, Manga says.
"The deeper water is stored, the warmer it will be. That heat provides the energy that drives the eruption," Manga says.
"At other geysers, that storage seems to be more shallow," he explains. "And our hypothesis for the reason why Steamboat is such a huge geyser and so tall is that the water is stored deeper. The deeper the water is stored, the more energy it can have. And the more energy you have, the bigger the eruption can be."
Some of the first studies of geysers were done in the 1800s, by Robert Bunsen — the same guy who developed the Bunsen burner used in chemistry classes. Scientists have put video cameras in geysers and have built artificial geysers in the lab.
Still, it's not so easy to find funding to study something like geysers, and the list of unanswered questions goes on and on, Manga says.
He rattles off a list: "Why do geysers exist in the first place? What is it about the geometry that makes something become episodic? Why do eruptions end? Why don't they just continue? How do geysers respond to external forces? What controls how high a geyser eruption is?"
Millions of people travel to see geysers each year, and part of the draw may be their air of mystery. Steamboat has become a superstar, eclipsing even Old Faithful in terms of public attention and the effort people make to try to catch an eruption.
"There are people that camp on the sidewalks, spend all of their days, all of their time off, sitting next to Steamboat," White says.
DAVID GREENE, HOST:
Steamboat Geyser in Yellowstone National Park can shoot water up more than 300 feet. It is the tallest active geyser in the entire world. And this year, it has erupted more times than ever before. This streak of activity has thrilled both casual tourists as well as committed geyser gazers. Scientists have been watching as well to try to figure out what exactly is going on. Here's NPR's Nell Greenfieldboyce.
NELL GREENFIELDBOYCE, BYLINE: Steamboat has become a geyser superstar, eclipsing even Old Faithful in terms of public attention. Erin White is Yellowstone's Park hydrologist.
ERIN WHITE: There are people that camp on the sidewalks, you know, spend all of their days, all of their time off sitting next to Steamboat.
GREENFIELDBOYCE: In videos, you can hear people's excitement when all that waiting pays off.
(SOUNDBITE OF PEOPLE CHEERING)
GREENFIELDBOYCE: White remembers when she got to see Steamboat. Last winter, she was driving past and stopped when she spotted a column of steam.
WHITE: And had the very unique experience of being the only person standing next to Steamboat while it was vigorously releasing steam. It is incredibly powerful. It's like standing next to a jet engine.
GREENFIELDBOYCE: Steamboat's had a record year - more than 45 eruptions. That beats the record set last year - 32 eruptions. And in the three years before that, there were zero eruptions. This geyser is not dependable like Old Faithful. The frequency of its eruptions is highly variable. Its sometimes goes quiet for a long time.
WHITE: In the 1960s, there was another period where there were more than 20 eruptions per year. And then prior to that, you know, there were dormant periods of more than 50 years.
GREENFIELDBOYCE: So what changed in 2018 to make this geyser start erupting every seven to 10 days? Scientists wish they knew. White says they've long understood the basic ingredients needed to make a geyser.
WHITE: You need to have a source of water. You need a source of heat. And you need structure - a geologic structure that is constrained or confined in some way to develop pressure that will generate an eruption.
GREENFIELDBOYCE: That combination is rare. The planet has fewer than a thousand geysers. About half are in Yellowstone, where an ancient volcano's magma heats water in underground cavities. You might think scientists would have detailed maps of what's going on beneath Steamboat, but White says they don't.
WHITE: What is the subsurface architecture? What is the volume of water that is available for every eruption?
GREENFIELDBOYCE: They do have temperature sensors deployed around the geyser. And there's been recent research using arrays of seismic sensors. Michael Manga is a researcher at the University of California Berkeley.
MICHAEL MANGA: People always ask, well, why is Steamboat such a tall geyser? And we can't answer that question.
GREENFIELDBOYCE: Not yet, anyway. Recent results show that Steamboat's liquid is stored at depths of about 65 to 130 feet. Manga says the deeper water is stored, the warmer it will be. The heat provides the energy that drives the eruption.
MANGA: At other geysers, that storage seems to be more shallow. And our hypothesis is - for the reason why Steamboat is such a huge guys are and so tall is that the water's stored deeper. The deeper the water's stored, the more energy it can have. And the more energy you have, the bigger the eruption can be.
GREENFIELDBOYCE: Some of the first studies of geysers were done back in the 1800s. by Robert Bunsen - you know, the same guy who developed the Bunsen burner used in chemistry class. Scientists who put video cameras in geysers and built artificial geysers in the lab. Still, many fundamental questions remain unanswered, like what makes some geysers so predictable? Manga says take one of his favorite geysers in Chile.
MANGA: When we were studying it, it erupted thousands of times. And the time between eruptions varied by less than about a second.
GREENFIELDBOYCE: When I started asking Manga about the geyser scientific community, he seemed kind of amused.
MANGA: It's interesting you say - expression geyser scientific community because it's a community of almost nobody.
GREENFIELDBOYCE: In fact, a couple of years ago, when he and a colleague wrote a review of geyser research for a science journal...
MANGA: We could cite just about every paper ever written about geysers, and there's very few fields where you can do that.
GREENFIELDBOYCE: He thinks the mystery is part of the allure of geysers like Steamboat. People like that there are fundamental things about the earth that we still don't understand. Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.