on retardant and aerial firefighting

I saw a good article on inciweb last week about retardant and aerial fire fighting. It is called Retarding the Flames, and it is one of the news releases in conjunction with the Station Fire:

One of the most dramatic sights on a wildfire is the vision of an air tanker releasing its red payload of retardant near the fire. Behind this picturesque vision is a long history of science in the development of a valuable tool for firefighters - the use of fire retardant. Today retardant is used when appropriate to help suppress wildland fires.

Aerial drops of retardant have come a long way since the first recorded water drop in 1930, when a Ford Tri-Motor airplane used a wooden beer keg filled with water. Now air tankers can drop 500 to 2000 gallons of retardant at a time to help suppress fires. Helitankers, which are helicopters with built-in tanks, can drop up to 2000 gallons; retrofitted DC-10s have an 11,000 gallon capacity, and Boeing 747s 20,000 gallons.

Fire retardant is just one of many tools in the arsenal of firefighters. Like any other tool, it must be used under the right conditions and for the right job in order to be effective. Firefighters consider many factors in deciding which tools to use at a particular location and time to suppress a fire. Characteristics of the terrain, weather variables such as temperature, humidity, wind direction and force; the types of vegetation in the fire area; proximity to homes and other buildings; and the first priority of safety of the public and firefighters are all factors in choosing the right tools for the particular circumstances.

Retardant drops are most often used in extreme fire conditions. The retardant is usually dropped just ahead of the advancing edge of the fire and the flanks of the fire. This cools and so slows the fire, helping firefighters on the ground. It reduces the rate of spread and the intensity of fires, and slows larger, more damaging, and therefore can reduce the cost of fires. Often, using retardant to fight fires is the most effective and efficient method of assisting firefighters in protecting people, resources, private property and facilities. The remoteness of many wildland fires can delay the arrival of firefighting ground forces. Retardant drops can rapidly reduce the intensity and spread of the fire until firefighters can safely take action. Topography in the fire area and windy conditions are some of the factors limiting the effectiveness, and therefore the use, of retardant.  . . .

Go here to read the complete article