So far this year, unmanned aircraft have terrorized bighorn sheep in Utah's Zion National Park and crashed in front of campers trying to watch a sunset in the Grand Canyon. Now, the head ranger has had enough.

On Friday, the director of the National Park Service signed a decree saying that drones shall fly no more over the lands and waterways of the country's parks. The order comes after a similar order last month that banned the devices from Yellowstone.

"We embrace many activities in national parks because they enhance visitor experiences with the iconic natural, historic and cultural landscapes in our care. However, we have serious concerns about the negative impact that flying unmanned aircraft is having in parks," director Jonathan Jarvis said in a statement.

Jarvis's statement suggests the ban will be temporary as the Parks Service attempts to create a policy to address the use of unmanned aircraft in the parks. While the devices can be a nuisance if used irresponsibly, they also provide unique opportunities for photography and scientific research in the parks.

The ban comes at a time of growing tension over how to regulate the lightweight aircraft as they grow in popularity with hobbyists. Recent months have also seen an assault involving a drone at the beach and a lawsuit in which a search-and-rescue team is challenging the FAA for a right to use unmanned aircraft on missions.

Right now, the legal status of consumer drones is unclear since the FAA does not have clear authority over the devices below 700 feet.