New Thermal Drone Technique Emerges from Tragic Texas Flood

Drone team finds new way to use thermal imaging in disaster response

By DRONELIFE Features Editor Jim Magill

The search for a victim who was swept away by the massive floodwaters that inundated parts of Central Texas earlier this month has led to the development of an innovative use of drone mapping technology, which could prove to be a game-changer in searches for victims of future disasters.

Amarillo Police Lt. Shane Chadwick, working with drone assets from his department and pilots from the New Braunfels Police Department, helped develop the search technique in an effort to find the remains of Marble Falls Area Volunteer Fire Department Chief Michael Phillips.

Phillips was one of some 135 people who perished in the flooding that swept through the Texas Hill Country, July 4 and 5. Despite weeks-long efforts by numerous emergency response personnel and hundreds of volunteer searchers, tragically his body remains undiscovered.

Chadwick, who serves as director of the Amarillo Regional Crime Center and director of his department’s UAV program, said he was already in the Central Texas region, using several of his department’s drones to assist with a state-led investigation, when the disaster struck and he was called on to aid in the massive search effort.

“Prior to the floods, we were helping the Texas Rangers try to locate a cold-case homicide with multi-spectral cameras on our drones,” he said in an interview. His UAV team previously had helped state investigators solve a crime. “We had found a grave, a partial grave, back in 2023 using multi-spectral and near-infrared cameras on drones.”

In the wake of the deadly flooding, Alan Trevino, chief deputy for the Burnett County Sheriff’s Office, requested the Amarillo drone team’s help in the attempt to recover the remains of Phillips, whose Jeep had been swept off the road by the raging waters of Cow Creek.

Although the Jeep had been recovered, the fire chief’s body remained lost, likely buried somewhere amid the massive debris fields left in the aftermath of the floodwaters.

Chadwick said he was unsure if his drones would be able to help, but that he’d provide what assistance he could.

“I told him, ‘Look, it’s a long shot. I mean, we’d be using thermal — not multi-spectral — for that.’ But I said, ‘We’re going to be in the area anyway. I’d be glad to give it a shot,’” he said.

After finishing their work on the homicide case, Chadwick and fellow Amarillo officer Corporal Sy Slover arrived in Burnet County on July 14, with the four DJI Matrice 4T drones. There they teamed with two New Braunfels pilots, who were already using their own department’s drones to map the area.

“We were there for three days, so we literally worked 37 hours straight,” he recalls. “When you do the thermal, you wait for the earth to cool because the earth will drop about 20 to 25 degrees in the night hours. So, we went and started mapping at 2:00 a.m.”

The combined team of drone pilots mapped an area about nine miles long, along the banks of Cow Creek, collecting about 27,000 thermal images. Chadwick took this data to Gene Robinson, a well-known expert in the use of drones in search and rescue efforts, who was teaching at Austin Community College.

Time-sensitive mission

“Because our work relies on detecting very minute temperature differences in the earth and the soil, unfortunately we have to look at it from a decomposition standpoint,” Robinson said. “There is a lot of science involved in being able to determine when a body started producing heat from decomposition and how long (the temperature) would stay elevated, how it was de detectable, that sort of thing.”

Because the mission to narrow down the search area for a body was so time-sensitive, Robinson said he used a software package known as Loc8, developed by Canadian company Unmanned Systems Research, to analyze the thermal images and to narrow down to a few the number possible sites likely to hide a victim’s remains.

“We really couldn’t have done that without the software because drones will take literally thousands of images and it’s difficult to go through each one of those with a standard-issue, mark-one eyeball,” he said. Searching through multiple images of debris piles, some measuring as large as 60 feet long and 40 feet high, within about five hours, Robinson was able to distill the data down, to be able to identify 12 sites with a high potential for hiding a body.

Armed with that information, Chadwick’s team went back to the scene at 6 a.m. the following day and began taking a closer look at the sites that Robinson had identified. They found three sites that had additional evidence of decomposition activity and directed searchers on the ground to those targets.

Unfortunately, none of the remains found were those of human victims. Instead, researchers uncovered a sheep and two deer.

Chadwick said that while the effort to locate a victim in this case did not turn out as hoped, the attempt proved that drone-captured thermal images could be quickly analyzed and could be used more successfully in future searches.

“It was successful in that we do realize now that with decomposition from about day seven to about day 21, you can locate humans, most likely with a thermal, assuming they’re not buried too deep,” he said.

He added that most police agencies that have a drone program could duplicate his team’s accomplishment without having to invest in expensive new equipment.

“It’s funny because the question that was given to me from Alan Trevino was ‘What makes your drones any better than ours?’ And I said, ‘They’re not. Every department has that kind of technology,’” he said. “It’s just looking at it from a different idea.”

Robinson agreed that the techniques used to respond to the Texas Hill County floods would likely be incorporated in future drone disaster recovery efforts, with hoped-for better results. “To have been able to use the drone to cover that much area and to get that much information processed and distilled down was a pretty big feat,” he said.

Read more:

• Drones Join the Front Lines in Deadly Texas Flood Response
• Drones in Disaster: Why No-Fly Zones Matter During Texas Flood Rescue
• Rising Above the Storm: How Drones Are Revolutionizing NYC’s Disaster Response 12 Years After Hurricane Sandy

Jim Magill is a Houston-based writer with almost a quarter-century of experience covering technical and economic developments in the oil and gas industry. After retiring in December 2019 as a senior editor with S&P Global Platts, Jim began writing about emerging technologies, such as artificial intelligence, robots and drones, and the ways in which they’re contributing to our society. In addition to DroneLife, Jim is a contributor to Forbes.com and his work has appeared in the Houston Chronicle, U.S. News & World Report, and Unmanned Systems, a publication of the Association for Unmanned Vehicle Systems International