An acidic hot spring in Yellowstone 'dissolved' a tourist - and it's more common than you might think
Colin and Sable Scott, a brother and sister from Oregon, left the authorized area and walked around the Norris Geyser Basin in Wyoming to find a thermal pool to take a dip in. While Colin was leaning down to check the temperature in one hole, he slipped and fell into it.
"In a very short order, there was a significant amount of dissolving," Lorant Veress, a Yellowstone deputy chief ranger, told NBC affiliate KULR 8 last week.
Since 1870, at least 22 people have died from injuries related to thermal pools and geysers in the park. It's alarming that a person can tumble into a pool of water and there to be nothing left but a flip-flop, but there are a few reasons why this can happen.
The pools are really, really hot.
Firstly, Yellowstone park sits on top of a geologically active supervolcano. With magma bubbling so close to the surface, geysers and hot springs can reach burning temperatures.
The Scotts happened to choose the hottest thermal region in the park, where temperatures can reach 237 degrees Celsius (roughly 456 degrees Fahrenheit). That's hotter than the temperature you cook most food at in an oven.
They're also acidic - and unsafe.
Most of the water in the park is alkaline, but the water in the Norris Geyser Basin is highly acidic. This is because of hydro-thermal vents under the surface emitting chemicals. Microorganisms also break off pieces of surrounding rocks, which adds sulfuric acid to the pools. This highly acidic water bubbles to the surface where it can burn anyone that is exposed to it.
In 2012, a study published in the journal Geochemistry, Geophysics, Geosystems examined water that came from the Heart Lake Geyser Basin. They found that safe and unsafe water originates from the same underground spot, but they separate as they reach the surface.
Some microorganisms can live there, but humans melt.
Certain microorganisms called extremophiles have evolved to live in extreme conditions such as very high temperatures and acidity. These are what make the water look milky in colour.
However, the conditions are deadly for humans, and the water can cause fatal burns and break down human flesh and bone.
"It is wild and it hasn't been overly altered by people to make things a whole lot safer, it's got dangers," Veress said. "And a place like Yellowstone which is set aside because of the incredible geothermal resources that are here, all the more so."
In other words, stick to the path.