Spread Component - (as used in the NFDRS)

The Spread Component is a rating of the forward rate of spread of a headfire. Deeming states that "the spread component is numerically equal to the theoretical ideal rate of spread expressed in feet-per-minute." This carefully worded statement indicates both guidelines (it's theoretical) and cautions (it's ideal) that must be used when applying the SPread Component. Wind speed, slope and fine fuel moisture are key inputs in the calculations of the spread component, thus accounting for a high variability from day-to-day. The Spread Component is expressed on an open-ended scale; thus it has no upper limit.