Video: World's Largest Geyser Erupts at Yellowstone National Park

At about 5:30 a.m. local time on Thursday, Yellowstone's Steamboat Geyser erupted for the first time since September 2014.

"We don't really know the exact duration for the eruption at this time," Wendy Stovall, a U.S. Geological Survey scientist with the Yellowstone Volcano Observatory, told Newsweek, noting the eruption was definitely over for now.

 "It's possible that it will erupt again, Steamboat erupts sporadically," she added. "Eruptions can be several days apart or several months apart or years apart, very unpredictable."

USGS scientists and park staff stress that there's nothing to worry about in terms of the supervolcano underlying Yellowstone. 

"We have zero concerns that anything is happening volcanically," Stovall said, adding that there hasn't been a Yellowstone supervolcano eruption in more than 600,000 years. "There's been geysers erupting through that whole time and that doesn't mean that anything is happening with magma underground."

That said, geysers are indirectly triggered by magma that lies a couple of miles below ground. That magma heats a pocket of water trapped just below Earth's surface. 

"There's basically a shallow reservoir of boiling water," Stovall said.

Every once in a while, the pressure in that pocket of boiling water builds up enough to break through the thin ceiling.

In addition to the geyser itself, the area around Steamboat got in on the action as well.

"There was a mudpot that was kind of pulsing, and there were several places where hot muddy water were spurting up," Stovall said.

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While there's no risk of volcanic activity following the geyser, USGS and park staff are continuing to monitor the site. Those monitoring systems, like a thermometer located at Steamboat's outlet channel and a nearby seismic sensor, are what told them the geyser was erupting in the first place. The hope that studying the data in more detail may one day yield clues that help scientists actually predict an eruption, something that isn't possible right now.

03_19_yellowstone_steamboat_geyser Steamboat Geyser as seen during its last major eruption, on September 4, 2014. Jim Peaco/Yellowstone National Park/Flickr

According to Vicki Regula, a public affairs assistant at Yellowstone National Park, the area around it is still closed for the winter. If there had been visitors in the area, the park would have blocked off the immediate vicinity for safety. 

"[The plume] can be more than 300 feet, and the water is spraying, and there can be debris," she said. (That 300-foot plume earns Steamboat the title of tallest active geyser in the world.)

Stovall didn't see this eruption and hasn't seen Steamboat Geyser in action before, but has seen other geysers erupting at Yellowstone. 

"It's majestic, it's kind of surprising," she said. "Even though I've seen photos and videos of geysers erupting, to witness one in person it kind of touches you in a different way."