Drones Make Rain to Fight Massive Wildfires in China

BY Zacc Dukowitz
23 November 2022

Using drones to create rainfall is an idea that’s been tested and reported on, but we haven’t heard much about it actually being implemented in the field—until now.

Toward the end of the summer, the approach was used in Chongqing, China to fight a series of devastating wildfires brought on by a historic heatwave.

Chongqing has a population of 31 million. In late August, wildfires spread quickly over the three mountain ranges in which the city is situated, threatening to engulf it.

chongqing-wildfire-jouav
Firefighters battle a blaze in Chongqing | Credit: JOUAV

Over 20,000 people joined the firefighting operation in Chongqing. Many of them were volunteers from the city who pitched in to help fight the fire, chopping down trees to make firebreaks and taking risks to deliver materials and equipment by motorcycle to fire personnel on the frontlines.

In addition to this volunteer work, a huge fleet of drones was deployed to help in a variety of ways, including delivering food and water, providing aerial surveillance, and carrying supplies.

Drones were also used to make rain.

During the firefight huge, long-range drones flew high over the fire carrying bars of silver iodide. Once within the clouds the bars were ignited, forming water droplets that created artificial rainfall in a process called cloud-seeding.

The long-range drone deployed for cloud-seeding during the Chongqing fires is called the Wing Loong-2H. It was designed by a subsidiary of a defense contractor named AVIC, which is owned by the Chinese government.

Chongqing isn’t the only place in China where cloud-seeding was used this summer.

In Sichuan, two cloud-seeding drones were used to spread rain over an area of 2,317 square miles in an operation that took five days to help combat fires there. The first of these efforts created rainfall in just sixty minutes.

Around the same time, cloud-seeding was also employed in Sichuan to avoid losing the harvest there due to drought. Using drones, rain was induced in the area to save the threatened crops.

China’s Huge Drone Fleets for Fighting Wildfires

In China, a variety of drones are deployed during wildfires, amounting to what has been called a “drone army” for firefighting. During the fires in Chongqing the full arsenal of China’s drone capabilities was on display, with an array of drones employed for a variety of firefighting work.

Here are all the ways that drones helped fight the wildfires in Chongqing.

Deliveries

Smaller delivery drones carried food and water to those involved in firefighting operations in Chongqing.

Also, large-load drones carried water pipes and emergency supplies to the frontlines of the fire fight. From there, some of these heavy lift drones were reloaded and deployed to specific destinations to bring the exact supplies needed to those helping with the firefight.

Monitoring and Surveillance

Drones equipped with thermal cameras were used to find potential hot spots, detect on-fire sites, monitor residual fires, and look out for places where the fire was in danger of reigniting.

Drones were also used for surveillance, watching the fire’s path and helping firefighters coordinate their efforts in real time, both at night and during the day.

Live visual and thermal feeds from drones were transmitted back to a tactical command center for the firefighting operation using 5G networking, allowing for real-time tracking of the fire’s movements to support emergency response coordination.

Search and Rescue

Drones equipped with visual and thermal sensors were used to look for and save people trapped or lost during the fires, helping save lives.

Dropping Fire Retardant “Bombs” by Drone

Drones were used to “bomb” burning areas with fire retardants, dropping small containers filled with chemicals designed to help put out fires, as shown in the video below.

Making Rain

Large, long-range drones were used for cloud-seeding over the fires, dousing them with artificial rainfall.

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A cloud-seeding drone preparing for takeoff

How U.S. Firefighting Operations Use Drones

U.S. firefighters are also starting to adopt new types of drone operations to fight fires.

The most common use for drones in U.S. firefighting work is for monitoring and surveillance. The Bureau of Land Management currently uses drones to monitor wildfires and controlled burns on federal lands, and dozens of municipal fire departments use drones for collecting aerial data during a fire and for post-fire investigations.

Although still new and somewhat controversial, cloud-seeding is starting to see some adoption in the U.S. At the moment, at least eight states are doing cloud-seeding with drones or planes.

Other drone firefighting use cases are being developed in the U.S. as well.

Researchers at the University of Kansas have created a drone for firefighting called the KHawk. The KHawk is designed to fly over wildfires and collect geolocational data about a fire’s trajectory, even in smoky or very windy conditions, as well as data on wind speed in the area.

U.S. company Drone Amplified has created a system called IGNIS, which attaches to a drone to let it drop chemical spheres that ignite fires. These intentional fires are called backburns—fires that make a defensive barrier for firefighting operations, steering wildfires into a chosen direction.

Drone Amplified - IGNIS Setup

The IGNIS system was originally made to be attached to DJI drones, which has presented a problem for adoption, since data privacy issues have led to some fire departments and firefighting agencies to halt their use of DJI drones—even if they already own several of them.

These concerns may not be well founded, especially when weighed against the benefits of using the technology for fighting fires. After all, a wildfire is not usually the site of sensitive infrastructure.

There’s a real need for more drones to be used in good ways on wildfires. With additional safety barriers in place, for these really low-risk, non-national security missions, I still think there’s very little risk of using DJI drones.

– Carrick Detweiler, CEO of Drone Amplified

The perception that DJI and other Chinese-made drones can’t be trusted may be creating a lag in drone adoption for a variety of firefighting work, putting Chinese firefighting operations ahead of the U.S. in terms of the sheer amount of drones used to fight fires, the types used, and the number of places where they’re used.

Increasing drone adoption for firefighting in the U.S. will require either the rise of comparable drones manufactured here, at comparable prices, or a change in the perception of risk for the use of DJI drones.

Most likely, the future holds some mixture of these two possibilities, with fire departments continuing to use DJI technology, though perhaps a little warily, while U.S. companies work to create competitive alternatives at scale.

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