The movement of fire across a landscape, often measured as m sec-1 or ft sec-1.
The speed at which a wildfire is growing in size. It is expressed as rate of increase of the total perimeter of the wildfire, as rate of forward spread of the wildfire front or as rate of increase in area, depending on the intended use of the information. Usually, it is expressed in chains or acres per hour for a specific period in the wildfire's history.
A fire behavior term used to express relative horizontal growth of a wildland fire. Expressed in total perimeter growth in chains per hour. One chain equals 66 feet.
The relative activity of a fire in extending its horizontal dimensions. It is expressed as a rate of increase of the total perimeter of the fire, as rate of forward spread of the fire front, or as rate of increase in area, depending on the intended use of the information. Usually it is expressed in chains or acres per hour for a specific period in the fire's history.
the speed at which a fire extends its horizontal dimensions, expressed in terms of distance per unit area of time. Generally thought of in terms of a fire's forward movement or head fire rate of spread, but also applicable to backfire and flank fire rate of spread.
The speed a fire travels, generally expressed as chains/hour.
