A 13-foot-wide hot pool formed over the winter in one of Yellowstone’s most active areas, and it could offer new insights into the park's ever-changing geothermal systems.

"The discovery emphasizes the dynamic nature of Yellowstone's thermal activity," Yellowstone Volcano Observatory's Mike Poland said.

Last April, geologists conducting routine maintenance at temperature logging stations in Yellowstone National Park’s Norris Geyser Basin found something unexpected: a previously undocumented thermal pool of blue water.