High winds in California have fueled the wildfires in more ways than one.
Not only have the gusts led to the rapid spread of multiple fires that have killed at least 24 people, displaced thousands of others and destroyed more than 12,000 structures, they have also grounded aircraft that are flying fire suppression missions.
Planes dumping water and retardant on impacted areas have been unable to take to the sky at times since the fires began because of the dangerous conditions presented by the winds.
Get top local stories in San Diego delivered to you every morning. Sign up for NBC San Diego's News Headlines newsletter.
Sustained winds over 40 miles per hour and high-velocity gusts impact a plane's ability to safely approach and depart a targeted area, while also impacting its water and retardant drop accuracy, a member of the California Department of Forestry and Fire Protection told reporters Monday.
"So, each aircraft will have that limitation based on the manufacturer's recommendation, and then as far as the safety component, usually the limiting factor is gusts over 30 miles an hour," he said. "But the sustained winds, anything over 40 is pretty much going to ground most aircrafts."
Sustained winds of up to 40 mph and gusts in the mountains reaching 65 mph are predicted through Wednesday, forecasters said. The National Weather Service issued a rare warning about a “particularly dangerous situation” related to severe fire conditions beginning overnight Monday into Tuesday.
Local
With winds picking up, aerial support could once again be grounded.
What kind of planes are used to fight fires?
The California Department of Forestry and Fire Protection, also known as Cal Fire, has a fleet of more than 60 aircraft operating from 14 airfields and 11 helicopter bases across the state, making it the largest civil aerial firefighting fleet in the world, per its website.
The primary aircraft used are tactical planes, helicopters and airtankers.
Tactical planes - primarily North American Rockwell OV-10 aircraft - monitor fires and serve as the primary aerial communication between other aircraft and commanders on the ground.
Helicopters, like the Bell UH-1H Super Huey, carry a bucket below the aircraft that contains about 320 gallons of water to be dumped on the flames. The Sikorsky S70i Hawk has a fixed tank containing 1,000 gallons of water or foam with pilot-controlled drop volumes.
Airtankers, specifically the Grumman S-2T tanker used for fast initial attacks on fires, hold roughly 1,200 gallons of retardant that can be dropped on the perimeter of the blaze. The tankers loop from the fire to the air base, where aircraft like the S-2T tanker can be refilled on the ground within minutes.
Cal Fire also has seven new airtankers that were put into service in 2024 called the C-130 Hercules, which each hold 4,000 gallons of fire retardant. According to Reuters, Cal Fire can also employ contractors to bring in Large Air Tankers (LATs) and Very Large Air Tankers (VLATs), which are typically passenger jets converted to tankers with external water tanks.
Super Scooper planes load their tanks by skimming the surface of open bodies of water. After the water is dropped above the flames, the aircraft returns to the body of water to replenish their tank and repeats the process until fuel is needed.
What is in the pink fire retardant dropped by planes?
According to Cal Fire, fire retardant is 88% water and 12% ammonium phosphate, the fire-retardant component that is commonly found in fertilizers.
"Other ingredients includes gum thickeners to help retardant stick to vegetation, flow conditioner to allow for easier transfer and mixing, and red coloring to help pilots see the fire retardant from the sky," per the Cal Fire website.
Is fire retardant safe?
Fire Retardant is not considered hazardous for potential respiratory side effects, according to Cal Fire. It may cause skin irritation due to the ammonium but typically can be removed with soap and water.
For domestic or farm animals, there are no known adverse side effects, but reactions may vary. Cal Fire advises pet owners whose animals eat significant amounts of vegetation that may be coated with fire retardant to consult a veterinarian.