Los Angeles County neighborhoods were painted red this week as planes flew -- and continue to fly -- overhead, dropping red clouds over communities scorched from several recent wildfires, including the ongoing Palisades and Eaton fires.
It's apparent that these red trails are used to stop the spread of wildfires, but what makes up fire retardant and why is it different than only using water to fight wildfires?
The trail of red clouds dropped over wildfires is known as Phos-Chek. This is a brand of long-term fire retardant. It has been used to fight fires since the 1960s, according to AccuWeather.
Components of the fire retardant include phosphate and sulfate salts mixed with clay to thicken the product. It contains roughly 85% water, 10% fertilizer and 5% minor ingredients, according to the USDA.
The fertilizer salts alter a wildfire's burns to lower the intensity and slow the spread. This occurs even once the water has evaporated in the fire, according to the USDA. The water in long-term fire retardant is mainly used to disperse the fertilizers over the wildfire uniformly. Fire retardant also saves on the use of water to expel flames.
Colorants are mixed into the fire retardant to make it visible, according to the USDA. This allows pilots to see where it has been dropped and accurately aim for later drops. If retardant lines aren't connected, wildfires can burn in the gaps.
Kate Kealey is a general assignment reporter for the Des Moines Register. Reach her at kkealey@registermedia.com or follow her on Twitter at @Kkealey17.