Any part of a fireline rendered useless by a breakover of the fire.

The leading edge of a relatively warm air mass which moves in such a way that warm air replaces colder air that moves away from a region. Winds associated with warm frontal activity are usually light and mixing is limited. The atmosphere is relatively stable when compared to cold front activity.

Amount of heat required to raise 1 pound of water 1 degree Fahrenheit (from 59.50 to 60.50 F), measured at standard atmospheric pressure.

Time used by an airtanker or helitanker to reload and return to the fire.

Status of a federal casual or federal regular government employee used for timekeeping purposes. An employee will be considered off duty and time spent in an on-call status shall not be considered hours of work if: 1) The employee is allowed to leave a telephone number or to carry an electronic device for the purpose of being contacted, even though the employee is required to remain within a reasonable call-back radius; or 2) The employee is allowed to make arrangements such that any work which may arise during the on-call period will be performed by another person.

Period(s) of the year during which wildland fires are likely to occur, spread, and affect resources values sufficient to warrant organized fire management activities.

A valve in which fluid flow is controlled by a ball with a hole drilled through it. In one position, fluid flows through the hole. When the valve is turned 90 degrees (1/4 turn) the hole is perpendicular to the flow and the ball stops the flow. Intermediate valve positions can be used to adjust the flow. 

A hose-coupling device having two male thread nipples for connecting hose and for connecting two female couplings of the same diameter.

Abbreviated (NH) for national hose. Specifically defined screw thread used on fire hose couplings.

Moisture content that a fuel particle will attain if exposed for an infinite period in an environment of specified constant temperature and humidity. When a fuel particle reaches equilibrium moisture content, net exchange of moisture between it and its environment is zero.