A progressive line construction duty involving self-sufficient crews which build fire line until the end of the operational period, remain at or near the point while off duty, and begin building fireline the next operational period where they left off.

Foam with an expansion between 201:1 and 1000:1.

An off-incident location at which emergency service personnel and equipment are temporarily located pending assignment, release, or reassignment.

Fire hose having two cotton or other fiber jackets outside the rubber lining or tubing.

The number of subordinates for which a supervisor is responsible, usually expressed as the ratio of supervisors to individuals. The optimum ratio is five-to-one.

Adjective class representing the degree to which the sky is obscured by clouds. In weather forecast terminology, expected cloud cover of about 0.7 or more warrants use of this term. In the National Fire Danger Rating System, 0.6 or more cloud cover is termed "cloudy."

Combustion of the twigs, and needles or leaves of a tree during a fire.

Condition in which obscuring phenomenon restricts horizontal visibility to six statute miles (10 km.) or less.

All control line that still contains the fire when mopup is completed. Excludes lost line, natural barriers not backfired, and unused secondary lines.

Particulate matter of mass median aerodynamic diameter (MMAD) less than or equal to 10 micrometers.