The process of agitating foam solution and air within a confined space (usually a hose) that produces tiny, uniform bubbles - the length and type of hose determine the amount of scrubbing and, therefore, foam quality.

Observers are posted at one or more strategic locations in the proximity of a fire to detect and warn fire personnel of pending critical weather changes that might significantly affect the fire.

A common VHF-FM frequency used by natural resource agency aircraft for emergency radio transmissions.

Wind, in miles per hour, measured at 20 feet above open, level ground or as adjusted to meet this standard to compensate for height of ground cover, uneven ground, and nearby obstructions.

Injury suffered as the result of a fire that requires (or should require) treatment by a practitioner of medicine within one year of the fire, regardless of whether treatment was actually received.

That portion of the total fuel that would actually burn under various environmental conditions.

Retardant drop made from one compartment at a time from an airtanker with a multi-compartment tank.

Insignificant change in wind speed, direction, and temperature (less than 5 degrees) and relative humidity (less than five percent), respectively. When used as a general statement in a long-range forecast, all four criteria apply.

The apparatus and techniques used to mix concentrate with water to make solution, pump and mix air and solution to make foam, and transport and apply foam. (Systems defined here include compressed air foam and nozzle aspirated.)

All items for transport and delivery by aircraft.