Lifting off above the Klondike fire, a specially designed drone that sounds like a mosquito on steroids disappears quickly into the dense haze.
Its mission: to drop ping-pong-sized balls from the air into rugged, inaccessible areas. The balls, filled with potassium permanganate, are injected with antifreeze prior to being released, and they ignite when they hit the ground, setting off back burns to create a defensive line on the eastern flank of the 38,382-acre fire, which is only 15 percent contained.
“They put it in areas where it wouldn’t be safe to send people in,” said Brentwood Reid, public information officer for the Klondike fire.
The Office of Aviation Services for the U.S. Department of Interior is testing these specialized and sometimes finicky drones for the first time on the wildfires burning in Southern Oregon.
The drones are equipped with infrared cameras and a hopper filled with the incendiary ping-pong balls, and fire managers are putting the delicate craft to work in a number of treacherous situations, operating both day and night.
“This is very highly accurate,” said Steve Stroud, fleet manager with the Office of Aviation. “We can drop a ball within 30 feet of a target.”
Not only can the drones release balls with great accuracy, they can find hot spots that are difficult to detect with helicopters or planes because those craft operate at higher altitudes or can’t fly when the smoke becomes too thick.
The drones are also useful in guiding helicopters through forested areas.
When the drone operator remotely guides the craft above a target, the spheres filled with potassium permanganate are dispensed from a hopper, and then injected with glycol, or antifreeze, before being dropped to the ground.
Once they hit the ground, the glycol ignites the potassium permanganate, and it sizzles and pops like a black snake firework on July 4.
Stroud said the drone is the same type many consumers could buy, but the hopper and dispenser are specialized Ignis components built by Drone Amplified, along with the infrared camera. The technology was developed by researchers at the University of Nebraska-Lincoln.
On the Klondike fire, there are two drones that drop the burning balls and a third that flies night reconnaissance.
Stroud and another fleet manager, Steve Ramaekers, spend a lot of time lying on the ground, cleaning and calibrating the dispenser before it’s sent off on another mission into dense smoke.
“We can fly in essentially zero visibility out to about five miles with this aircraft,” Stroud said.
Last Thursday, he had set up the portable drone operation center in a remote area to the northwest of Wonder, off Briggs Valley Road along the southwestern flank of the Klondike fire.
Fire managers generally set off the back burns near ridges and let the fires burn down the slope, which is easier to control than an uphill blaze — and it’s also easier to control the intensity of the fire.
The idea is to burn off the underbrush and leave most of the trees unscathed in order to create a dead zone of vegetation for the advancing Klondike fire.
Nearby, incident commanders were prepping for major back-burning operations along the southern flank of the fire. Hand crews were creating defensible spaces around homes and along roadways to make sure they remain unscathed during the intentional burn.
Helicopters, which also have ping-pong ball dispensers, likely would be used to start the bigger back burns, starting at the ridge and working the fire down to the road or some other control line.
Hand crews have spent days cutting away manzanita and other shrubs along miles of roadways, stacking the material up for chipper crews.
Fire managers are trying to create stronger lines around the Klondike, which has been catching up to the bigger 43,388-acre Taylor Creek fire and 40,302-acre Miles/Columbus/Snow Shoe/Round Top fires burning in Southern Oregon. The major fires are burning to the north and west of Medford.
The Klondike fire control line actually connects with the Taylor Creek perimeter, creating a line about 1,000 feet deep along the eastern front several miles to the west of Highway 199.
Traci Weaver, public information officer for the U.S. Forest Service and Bureau of Land Management, said the drones are among several types of aircraft available to fight the Taylor and Klondike fires.
She said the drones have proved invaluable as scouts that find hotspots, able to hover closer to active fire situations than humans.
“You can’t place a dollar figure on a person’s life,” she said. “We use all the tools in the tool kit that are effective.”
She said visibility has hampered firefighting operations on the Klondike fire.
“We tried to fly a DC-10 with a lead plane in front to mark the passage,” Weaver said. “We did six passes in six directions and couldn’t find a safe passage.”
She said dropping retardant in steep, rugged country sometimes has little effect because the retardant doesn’t filter through the canopy.
Weaver said she gets calls from the public wondering why retardant is dropped far from the fire. She said it’s sometimes more effective to drop along ridge lines where vegetation is sparser and where the retardant will have more effect.
Often retardant is used to slow a fire to give hand crews a chance to build lines.
“It’s like putting a little water on a campfire and walking away,” Weaver said, “and you’ve still got burning embers.”
Even bucket drops from helicopters can have little effect, particularly on windy days when the water dissipates before it hits the ground, she said.
Weaver said she expects drones will be used more and more in the coming years, both for reconnaissance, back burns and potentially other uses.
“We’re just starting to learn their potential,” she said.