It can also rate the difficulty of control in that fire. If one of these is conducive to fire and the other is not, there is no danger. Generally speaking, fire is not a possibility when there are green fuels and the weather is dry, windy, and hot. Nor is it a possibility when there are dead fuels and the weather is cool and wet. The potential for wildfires skyrockets.
Fire danger based on the condition of fuels is rated by a number of indices.
The spread component rates fire speed due to changes in wind v elocity and in dead and live fuel moisture content. The energy release component measures heat released in the flaming zone of the fire caused by variation in fuel moisture. The burning index, which is the most important fire danger index, rates the fireline intensity. This is where flame length is determined. These indices give specific data on flame lengths and how fast a fire spreads.