Emily Chan
Visitors walking among the hot springs in the Biscuit Basin at Yellowstone National Park were met with a violent surprise on the morning of July 23. According to the National Park Service, a hydrothermal eruption unleashed huge clouds of dust and steam, damaging a boardwalk and causing several park guests to flee to safety.
The explosion occurred around 10 a.m. local time at the Biscuit Basin thermal area, which is located just two miles north of the Old Faithful geyser. It appeared to originate near the Black Diamond Pool. Fortunately, no one was injured by the eruption.
Staff closed off the area to assess the damage. The U.S. Geological Survey (USGS) stated that the boardwalk “will need a few repairs.” Additionally, rocky debris and silt were scattered all over the area.
“What we saw today was spectacular and definitely hazardous,” said Michael Poland, a research physicist and the scientist in charge of the Yellowstone Volcano Observatory.
The eruption was likely triggered by blockages in the natural plumbing system underneath Yellowstone. Hydrothermal explosions occur when hot water in a volcano system turns into steam in a confined space. Sudden drops in pressure lead to rapid expansion of high-temperature fluids and spark an explosion.
This does not mean that the volcanic system beneath Yellowstone is becoming more active. The USGS states that volcanic activity in the Yellowstone region remains at normal levels.
Hydrothermal explosions are dramatic and powerful. They can reach heights of over a mile and spit out debris as far as two and a half miles. They are also one of the most poorly understood geologic hazards.
It is not the first time that such an eruption has taken place at the park. Yellowstone is a hotbed for hydrothermal explosions, occurring as many as a couple times per year. Every few hundred years, an explosion large enough to leave a crater the size of a football field should be expected.
According to Poland, the eruptions can happen anywhere that hydrothermal activity is present. Other hotbeds include New Zealand, Iceland, and Chile.
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