The Baffling Case of Colorado's Mystery Drones

Pictured: A drone deployed during a demonstration at the Los Angeles Fire Department ahead of DJI’s AirWorks September conference in Los Angeles.
Pictured: A drone deployed during a demonstration at the Los Angeles Fire Department ahead of DJI’s AirWorks September conference in Los Angeles.
Photo: Robyn Beck (Getty)

Local authorities are dumbfounded by a flock of drones that recently began performing nighttime flights over northeast Colorado with no apparent purpose or operators (at least, none they’ve been able to identify so far).  


Officials have spotted at least 17 drones flying over Phillips and Yuma counties for the last week, the Denver Post reported. They always come out between 7 p.m. and 10 p.m., according to Phillips County Sheriff Thomas Elliot, remaining about 200 to 300 feet in the air as they map out a square pattern. Rather slowly, I should add, as officials estimated these mystery drones were cruising at 30 or 40 miles per hour.

“They’ve been doing a grid search, a grid pattern. They fly one square and then they fly another square,” Elliott told the Post.

The drones—which Elliott estimates have about a six-foot wingspan—have also been spotted creepily hovering over towns or empty fields for hours, identifiable by their distinctive strobing lights that flash white, red, blue, and green

So far, the DEA, the FAA, the U.S. Air Force, and the U.S. Army Forces Command have all said they’re every bit as clueless as local officials about what these drones are doing and why.

Federal regulations mandate that drones weighing less than 55 pounds must be flown during daylight hours, within sight of the pilot, and keep below 400 feet above the ground. There are also additional rules for restricted airspaces, such as near an airport or over certain emergency sites. Based on their size, it would appear these mystery drones would exceed that weight limit, and officials said they weren’t flying in any restricted airspaces. Just being generally creepy.

“They do not seem to be malicious,” Elliott said. “They don’t seem to be doing anything that would indicate criminal activity.”


Currently, drone pilots aren’t required to broadcast their drone’s position or who is pulling its strings, but that could change with new regulations recently proposed by the FAA. However, these new FAA rules, which would require operators to broadcast this information via radio frequency or through the internet, are estimated to take at least three years to implement if approved, per a Bloomberg report. So, for the immediate future at least, Colorado officials are on their own solving this mystery behind these nighttime drone flights.  

With the timing of all this, Elliott joked that the sheriff’s office had ruled out Santa and his reindeer as a possible explanation. As the experienced tech reporter I am, I’d like to posit another entirely plausible theory: Aliens.


Gizmodo weekend editor. Freelance games reporter. Full-time disaster bi.



From the linked article:

The grid pattern suggests the drone operators might be creating a map or carrying out a search, Moss said, although he added that some drone operators will fly at night in order to use infrared cameras, which are sometimes used in agriculture to examine crops

There is a range of wavelengths called “infrared” going from near infrared, which borders the visible to the far infrared, which is used in thermal imaging.

The near infrared is used to check crops because leaves reflect near infrared (part of why it feels cooler under leafy trees), but that is best observed when there is a large near infrared source, such as the sun, shining on them. AFAIK plants aren’t particular producers of thermal energy unless they are on fire, so thermal imaging at night, though probably making it easier to spot warm blooded animals, would not help much with agriculture.

I can believe it when they say the drones appear to be working on a grid pattern, possibly with some high-resolution monochromatic camera and are using various light sources to build up an image; that’s usually what NASA has done with it’s best cameras for maximum resolution, but usually it’s done with sun shine and colored filters as the level of illumination is higher. The one difference is that a drone mounted light would allow control of the direction/shadows, but it would require significant intensity.

What’s missing are any video recordings. Certainly someone should have been able to get a smartphone out while the drones are tooling about, even just to see the lights move a bit.

One thing I guess at is the report of one which parked “motionless”. If it was using a camera to provide an external location and altitude reference then it could relay GPS errors from that position to the other drones to increase the precision of the operation/location of the remaining drones. This is typically done in ground-based surveying by having a device at a known location, but there might be cases when the remaining drones would not be able to maintain line-of-sight contact for radio updates from a ground location.