YELLOWSTONE NATIONAL PARK — Yellowstone National Park’s huge Steamboat Geyser is erupting less often than at any time since it came back to life more than three years ago.
Beginning in 2018, a lucky few people would cheer loudly when they saw Steamboat Geyser thunder to life, shooting 300 feet or more into the air while sounding like a jet engine.
But Steamboat, the world’s tallest active geyser, was spoiling its fans, erupting on average every five to 10 days. The brakes went on in May of this year. Since then, it has erupted only twice.
“Well you know, Steamboat may be slowing down,” says Dr. Michael Poland, the Scientist in Charge of the Yellowstone Volcano Observatory. He went on to say, “This is just something that we sort of expected would eventually happen because Steamboat does go in cycles.”
Even though geyser watchers were thrilled when Steamboat roared back to life in March of 2018, after being inactive for more than four years, it was still extremely difficult to actually see one of its major, 300-foot tall eruptions.
In 2018 it went off 32 times. Then in 2019 and again in 2020, it had 48 major eruptions each year. So far in 2021, there have been 13 eruptions. That seems like a lot, but Steamboat is completely unpredictable. It might go off at any time of the day or night so being right there to see it when it awakes takes a lot of luck or a lot of patience.
At times your patience with the geyser would have had to be enormous. It once fell dormant, for 50 years, from 1911 until 1961.
Since then it has gone through cycles of rest and activity. Until 2018, the most major eruptions recorded for Steamboat in a single year was 29 in 1964. Since 1990 it has twice paused more than 8 years between eruptions with no warning about when it would stop or start.
“That’s one of the interesting things about Steamboat. It doesn’t appear to give any obvious signs it’s going to be in one of these eruptive phases or not," Poland said.
But that doesn’t mean scientists are completely in the dark. They’ve long known the general map of how Yellowstone is affected by the hot, deep inner mantel of the earth and have recently used sound waves to map Steamboat closer to the surface.
“And so the geysers really don’t reflect what’s happening at depth. They’re related, right? The deep magmatic system provides the heat that heats up the water that gives you the geyser but then that hydrothermal system that sits on top of it is somewhat independent.” Said Poland.
The west is in a drought and it would seem to make sense that could be affecting the geyser.
Poland said he’s convinced that could be true. “So it’s always in the back of my mind that water, we know it plays a role, how much of a role it plays at Steamboat specifically, is still unknown.” He said.
There are other signs linked to water. Cistern Spring (see photo), located nearby, will completely drain of water shortly after a Steamboat eruption. It refills after a few days. Poland said while that has been observed for some time, the actual underground water connection has not yet been found.
But Poland has also observed something else, a sort of poker, “tell” that the geyser is working up to a major eruption. He said, “If it’s very active with minor geysering, probably a major is potentially on the way. “
Poland visited Steamboat about two weeks ago to check on and repair some of his instruments. He noticed just that. Poland said, “And sure enough it was having a lot of minor activity so I was sort of expecting that at some point we were going to see a major.”
His intuition was right. Just a few days after he left, the most recent major eruption spewed out. It happened on July 8, at 6:34 a.m. It had been 37 days and 18 hours since the last eruption. That’s the longest gap since 2018.
Steamboat’s recent slowdown may disappoint geyser watchers, but scientists say that change is good news for them.
“Even though it may not be as exciting because we don’t have eruptions every five days like we have the last three summers, scientifically it’s a pretty exciting time because this is the time that we learn the most about how these geysers work," Poland said.
While Steamboat is the tallest geyser in the world right now, it hasn’t always been that way. A geyser in New Zealand, Waimangu, used to shoot 1,600 feet into the air. But it hasn’t gone off in 117 years.
Even in Yellowstone, Excelsior Geyser in the Midway geyser basin, not far from Grand Prismatic Spring, used to be just as tall but hasn’t gone off since 1985.
And Semi-Centennial Geyser near the Roaring Mountain, north of Steamboat, was just as tall but has been dormant for 99 years.
