A tourist has crashed a drone into Yellowstone National Park's world-renowned Grand Prismatic Spring, potentially damaging it, park officials said.
The crash into the park's largest hot spring came less than two months after the National Park Service banned the use of drones and small remote-controlled aircraft at all 401 national parks and monuments.
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"People unfortunately sometimes treat hot springs like wishing wells. But this is the first unmanned aircraft," said park spokeswoman Amy Bartlett. "Grand Prismatic is one of our biggest hot springs, a highly visited spot, and you don't want anything entering it."
The crash happened Saturday, Bartlett said, and the pilot told park officials that it had happened and then left the area. Park rangers are now trying to track down the pilot to get more information about the size of the drone — they're often smaller than a pizza box — and exactly where in the spring it crashed.
Grand Prismatic is known for the bright multi-hued algae and bacteria coloring its edges, and the deep blue color at the center of its approximately 200-foot-wide pool. Visitors aren't allowed to walk up to the water's edge, and must remain on a boardwalk set back from the shoreline.
Bartlett said park rangers have been unable to see the drone from the boardwalk. They may have to fly over the spring in a helicopter so they can get a better look. She said rangers worry the drone's presence could damage the spring, but removing it might cause even more damage.
Because hot springs depend on water welling up from within the earth, anything that blocks or alters the waters' flow can change the spring's appearance. That means the drone might plug up the spring, but so could a rock accidentally dislodged by a ranger trying to retrieve the craft.
The park has not erected signs telling visitors about the ban on drones, but that information is printed in the park newspaper given to visitors.
Bartlett said the park worker who was told about the crash by the drone's pilot apparently didn't recognize the gravity of the situation. Citing the ongoing investigation, she declined to provide further details about the incident.
"We would just like some more details from the person," she said.