Geologists discovered a new blue water spring at Yellowstone National Park that likely formed after a series of “mildly explosive events,” the United States Geological Survey said.
The new pool was found in a subbasin at the Norris Geyser Basin, which is the park’s hottest and oldest thermal area. Scientists conducting routine maintenance in the area unearthed the spring in April, according to a July 14 release from USGS.
The hole is about 13 feet in diameter and 1 foot below the rim, USGS said. The water in the pool, which is light blue in color, was measured at 109°F.
USGS said satellite images indicate the spring formed in a series of events between December 2024 and February 2025.
Geologists believe it formed as a result of a hydrothermal explosion, which is when hot water within a volcano flashes to steam, breaking rocks and throwing them into the air.
More Yellowstone: Watch pair of baby bison run off the ‘zoomies’ at the park
New Yellowstone spring probably formed in ‘mildly explosive events’
Yellowstone’s new blue water spring “probably formed in a series of mildly explosive events” between late December 2024 and February 2025, USGS said.
Geologists discovered the hole in April after visiting the site for the first time since last fall, USGS said.
The pool was surrounded by small rocks that were covered in light-gray, sandy mud. The sides of the pool also appeared to have two exposed layers, but one was actually a coating left when the water was at a higher level, USGS said.
Both the presence of the rocks and the water layers are evidence of a hydrothermal explosion, according to USGS. Satellite images corroborated the findings that the hole formed over several months.
Can you swim in Yellowstone’s hot springs?
While hot springs are often popular swimming spots for visitors to national parks, it’s unlikely the one recently discovered at Yellowstone’s Norris Geyser Basin will allow bathing.
According to the National Park Service, Yellowstone has very limited spots for swimming because of extreme water temperatures.
The water in the park’s hot springs often reaches the boiling point, so swimming in them is prohibited to protect visitors as well as the park’s thermal environments, according to NPS.
On the other end of the spectrum, the park’s high-elevation lakes and rivers typically have cold water that can pose a risk of hypothermia, per NPS.
Melina Khan is a national trending reporter for USA TODAY. She can be reached at melina.khan@usatoday.com.
This article originally appeared on USA TODAY: Yellowstone National Park geologists find new blue water spring
