A pyrotechnic device specifically designed to initiate burning of a fuel mixture or propellant.

Area of change between advancing, lateral, and backing vectors.

Rain that freezes upon contact with objects on the ground.

The entire outer edge or boundary of a fire.

The vertical distance above ground scorched or blackened on a tree bole.

The area where the factors that principally determine home ignition potential during extreme wildfire behavior (high fire intensities and burning embers) are present. The characteristics of a home and its immediate surroundings within 100 feet comprise the HIZ.

The characteristics of a structure and its immediate surroundings within 100 feet; the SIZ may be extended (e.g., to 150 or 200 feet) in areas of steep terrain or dense, highly flammable vegetation. The SIZ is the key determinant for structure ignition potential during wildfire.

A communication aid designed to help firefighters develop an awareness of the local fire situation by providing a visual reference to fire danger rating.

The direction of fire spread identified as one of three categories: advancing, lateral, or backing.

Used to determine the aerobic capacity of fire suppression support personnel and assign physical fitness scores. The test consists of walking a specified distance, with or without a weighted pack, in a predetermined period of time, with altitude corrections.