By Laura Zuckerman
(Reuters) - Yellowstone National Park may use a helicopter to search for a drone that a tourist crashed into a famous hot spring, amid concerns the device may harm a geothermal feature that is a top draw for visitors, a park official said on Friday.
Although the National Park Service two months ago banned the use of unmanned aircraft, officials at parks in Western states are reporting a rise in the number of the camera-equipped devices buzzing wildlife and tourists and crashing into the scenery.
Yellowstone rangers have been unable to find the drone that sank in Grand Prismatic Spring on Saturday, and park managers are considering a helicopter flyover of the 370-foot diameter spring, park spokesman Al Nash said.
It remained unclear Friday if the drone would affect the prized hot spring, which is more than 120 feet deep and known for the brilliant colors caused by bacteria and minerals in the water.
"We can't make any educated decisions about what it might do or how we might retrieve it until we know more," Nash said. "This is truly uncharted territory for us."
Yellowstone has received offers of help from the public, Nash added, including a man who wanted to rent the park a second drone to find the missing one and the head of a company that conducts underwater expeditions.
Park officials say the desire to film wildlife and stunning views must be balanced against public safety and the protection of natural resources, along with complaints by some who say the low-flying drones have marred their experience at a park that spans parts of Wyoming, Montana and Idaho.
Earlier this summer, a camper asked authorities at Wyoming's Grand Teton National Park to extract his drone from a tree where it was stuck, Grand Teton spokeswoman Jackie Skaggs said.
"We explained to the gentleman drones were not allowed in the park and that we couldn't expend public money to retrieve his $1,400 toy," she said.
Someone else nabbed the drone and made away with it overnight, Skaggs said, adding that the authorities were investigating the incident as a case of stolen property.
(Reporting by Laura Zuckerman; Editing by Daniel Wallis and Leslie Adler)