Drone Mapping for California Wildfire research
Wildfire Interdisciplinary Research Center & San Jose State University
Background
California is the most wildfire prone state in the U.S., with fires burning an approximate 2,569,386 acres of California land across 7,396 fires in 2021. These uncontrolled fires pose a serious threat, damaging important infrastructure such as water, power, communications, or gas, as well as damaging property in their rapid spread. They destroy natural habitats for wildlife and significantly diminish air quality, which serve long-term harm to the ecosystem as well as human health. The rate of wildfires in California has increased annually since the 1980s, according to the EPA, making it more crucial than ever that we have an in-depth understanding of how fires spread and the effects they have.
Prescribed, controlled burns of this nature aren't just useful for research, though. These also serve as providing buffers in order to prevent future fires. In order to minimize the risk of future out of control burning, it is beneficial to have regular burns that can eliminate dead flora that may serve as future kindling. These burns can also help the land by eliminating invasive plant and insect species, opening land for new growth, and increasing the rate of nutrient return to soil.
About WIRC
The WIRC team
San Jose State's Wildfire Interdisciplinary Research Center (WIRC) are a group of researchers from a variety of disciplines and backgrounds studying California wildfires in order to collect data regarding environmental and social impacts of wildfires to better inform response and policy. Using the data they collect, the behavior of wildfires and their specific effects on the areas they inhabit, as well as the climate at large, are able to be modeled and predicted with precision. Their approach aims to work towards better solutions to wildfire-related problems through multiple fields of research, such as social, economic, and physical science-based solutions and actions.
Oct. 24th Burn
Aerial view of the October 24th Salinas burn site using a multispectral drone camera.
In October of 2022 at a canyon site in Salinas, California, the WIRC helmed the largest scale controlled canyon wildfire research ever taken. With collaboration from many industry partners and researchers from other groups and a plethora of technology and tools, including extensive drone mapping materials, a variety of data was able to be collected regarding the behavior of wildfires in environments like these canyons.
Aerial images of the researcher's & partner's vehicles, the canyon, and the fire from afar.
According to Dr. Clements of the WIRC, this site is especially useful as WIRC's data on canyon fire spread is limited, due in part to how difficult obtaining information on wildfire behavior in canyon locations can be. Canyon-based wildfires spread rapidly as fire climbs the canyon's sides, differing in behavior from fires in other terrains, such as wider or flatter fields. With this burn, we will have more information to use in predicting and modeling wildfires.
In order to ensure safety during a burn of this magnitude, the event was coordinated with CAL FIRE and held on private land. Many people from different backgrounds and specialties came to work on this large-scale burning.
Observation occurred at different locations, this image shows the lower site where the vehicle equipment was parked and where the drones were piloted from.
This Doppler-radar, owned by San Jose State, was one of the many tools used to collect data during this experiment. By scanning the plumes in the wildfire, it was able to determine wind speed and the growth and change of the fire plumes. Additional tools included the DJI Matrix (with thermal camera) and DJI Mavic drones, and a weather balloon for collecting particulate data.
A large area was burned with many devices actively collecting data, such as this drone footage captured by Bo Yang using a DJI Mavic. Here the parameters of the burn site can also be seen, as the burn was in a specified and predetermined location in order to ensure safety and that it would not spread beyond the decided boundaries.
The safety of the event was very important to everyone involved. The scores in the dirt in this image are known as fire breaks and serve to prevent the flames from going past their perscribed area.
Throughout the burn, the batteries of the drones needed to constantly be monitored and exchanged for fully charged ones. Batteries were constantly being charged and the process of switching out old and new batteries needed to be done extremely quickly to minimize the amount of downtime for the drones.
The drones were half a mile away from the pilots, meaning every swap required the process of switching the batteries, getting the drone back in air, flying it to the fire half a mile away, and then returning to repeat the process. The hot spots of the fire were constantly changing and needed to be found again by the pilot (Owen Hussey, Geography MA) each time to drone returned to the burn site.
The fire burned for approximately 3 hours, and the DJI Matrix's battery life lasted approximately 30 minutes - a lot of swaps had to occur!
But the footage that was collected was enlightening. Using infrared drone imaging, much more of the fire than is visible to the naked eye could be seen. While with our eyes only smoke is visible from the site, using the drone cameras the specific highest intensity areas and vortexes of the wild fire are visible to us through their heat. The drone here is being flown approximately 500 feet above the fire, directly in the smoke plume.
Owen Hussey shows the ash build-up on the DJI Matrix, which had a thermal imaging camera attached, as a result of flying directly above the wildfire.
Some of the stickers and labels on the drone were melted and warped from the sheer heat of the flames.
Footage of the site from above.
Drone Mapping
Using GIS and drone imaging, the exact extent of the burn can be calculated by comparing data collected before and after the burn occurred, as well as giving visual representation of the entire site of the wildfire from an angle we would not be able to see from the ground. With the infrared and hyperspectral cameras these drones have equipped, even more detail can be gathered from the sites, allowing for even more accurate modeling of these wildfires.
The drones serve as effective tools for collecting this information due to their portability and ease of use compared to other methods, such as helicopters. Drones are quick to set up and, pared to full aerial vehicles, are much easier to use. Even if they require additional power, as happened at the site, their batteries are easy to switch out (as could be seen from the many quick swaps that needed to happen at the Salinas site) and they are able to quickly get in the air and return to collecting information.
The drones were able to fly so quickly, in fact, that after the main fire ended, when an additional tree caught fire as the team was leaving, Dr. Yang was able to assemble a drone and fly it to the tree to collect footage within minutes, according to Hussey.
"For a wildfire event like this, where the fire moves and changes very rapidly, drones are kind of an unparalleled way to deploy quickly. They have very little downtime and are easy to reposition compared to other methods. There's little risk because you don’t have to get close—the most you risk is the drone and the equipment attached, so you can stay a safe distance and the quality of the data from a charter plane or satellite would be less just from the altitude. The equipment on these drones is very high resolution. It was a well suited platform to gather data and adjust on the fly to the conditions that were changing quickly due to the very nature of the wildfire." - Owen Hussey
